How to Read in a File Line by Line in Java Code Ranch
Imagine, you are developing Java software and of a sudden you lot encounter an error? Where could you accept possibly gone wrong?
There are many types of errors that you volition run into while developing Java software, but virtually are avoidable. Some errors are minor lapses when writing codes but that is very much mendable. If you have an error monitoring tool such as Stackify Retrace , you tin write codes with ease.
In this article you volition find:
- 50 of the most common Java software errors
- Lawmaking examples and tutorials to assist you work effectually mutual coding issues
Read on to larn almost the most common bug and their workarounds.
Compiler Errors
Compiler error messages are created when the Java software lawmaking is run through the compiler. It is important to recall that a compiler may throw many error letters for one fault. So, ready the first error and recompile. That could solve many problems.
1. "… expected"
This error occurs when something is missing from the code. Often this is created by a missing semicolon or closing parenthesis.
private static double volume(String solidom, double alturam, double areaBasem, double raiom) { double vol; if (solidom.equalsIgnoreCase("esfera"){ vol=(4.0/3)*Math.pi*Math.pow(raiom,3); } else { if (solidom.equalsIgnoreCase("cilindro") { vol=Math.pi*Math.pow(raiom,ii)*alturam; } else { vol=(1.0/3)*Math.pi*Math.pow(raiom,ii)*alturam; } } render vol; } Often this error bulletin does non pinpoint the verbal location of the issue. To find information technology:
- Brand sure all opening parenthesis have a corresponding closing parenthesis.
- Look in the line previous to the Java lawmaking line indicated. This Java software fault doesn't get noticed by the compiler until farther in the code.
- Sometimes a character such as an opening parenthesis shouldn't be in the Coffee code in the start place. And then the developer didn't place a closing parenthesis to balance the parentheses.
Check ut an instance of how a missed parenthesis can create an error ( @StackOverflow ).
two. "unclosed string literal"
The "unclosed cord literal" mistake message is created when the string literal ends without quotation marks and the message will appear on the same line as the error . (@DreamInCode) A literal is a source code of a value.
public abstruse course NFLPlayersReference { individual static Runningback[] nflplayersreference; private static Quarterback[] players; private static WideReceiver[] nflplayers; public static void master(String args[]){ Runningback r = new Runningback("Thomlinsion"); Quarterback q = new Quarterback("Tom Brady"); WideReceiver w = new WideReceiver("Steve Smith"); NFLPlayersReference[] NFLPlayersReference; Run();// { NFLPlayersReference = new NFLPlayersReference [3]; nflplayersreference[0] = r; players[1] = q; nflplayers[2] = westward; for ( int i = 0; i < nflplayersreference.length; i++ ) { System.out.println("My name is " + " nflplayersreference[i].getName()); nflplayersreference[i].run(); nflplayersreference[i].run(); nflplayersreference[i].run(); Organisation.out.println("NFL offensive threats have corking running abilities!"); } } private static void Run() { System.out.println("Not yet implemented"); } } Commonly, this happens when:
- The string literal does not end with quote marks. This is piece of cake to correct past closing the cord literal with the needed quote mark.
- The cord literal extends across a line. Long string literals can be broken into multiple literals and concatenated with a plus sign ("+").
- Quote marks that are part of the string literal are not escaped with a backslash ("\").
Read a discussion of the unclosed string literal Java software error bulletin. ( @Quora )
3. "illegal offset of an expression"
There are numerous reasons why an "illegal first of an expression" fault occurs. It ends upwards being i of the less-helpful fault messages. Some developers say information technology's caused by bad code.
Usually, expressions are created to produce a new value or assign a value to a variable. The compiler expects to find an expression and cannot find it considering the syntax does not friction match expectations . ( @StackOverflow ) Information technology is in these statements that the fault can exist found.
} // ADD IT Here public void newShape(String shape) { switch (shape) { example "Line": Shape line = new Line(startX, startY, endX, endY); shapes.add(line); break; case "Oval": Shape oval = new Oval(startX, startY, endX, endY); shapes.add(oval); intermission; case "Rectangle": Shape rectangle = new Rectangle(startX, startY, endX, endY); shapes.add(rectangle); break; default: System.out.println("ERROR. Check logic."); } } } // REMOVE IT FROM Here } Browse discussions of how to troubleshoot the "illegal get-go of an expression" error. ( @StackOverflow )
iv. "cannot notice symbol"
This is a very mutual issue considering all identifiers in Coffee need to be alleged before they are used. When the code is existence compiled, the compiler does not understand what the identifier means.
There are many reasons you might receive the "cannot find symbol" message:
- The spelling of the identifier when alleged may not be the aforementioned as when information technology is used in the code.
- The variable was never declared.
- The variable is not beingness used in the same telescopic it was declared.
- The class was not imported.
Read a thorough give-and-take of the "cannot find symbol" error and several lawmaking examples that create the aforementioned issue. ( @StackOverflow )
5. "public class XXX should be in file"
The "public form XXX should be in file" message occurs when the class XXX and the Java programme filename do not lucifer . The code will only be compiled when the class and Java file are the same. ( @coderanch )
package javaapplication3; public class Robot { int xlocation; int ylocation; String name; static int ccount = 0; public Robot(int xxlocation, int yylocation, Cord nname) { xlocation = xxlocation; ylocation = yylocation; name = nname; ccount++; } } public class JavaApplication1 { public static void main(String[] args) { robot firstRobot = new Robot(34,51,"yossi"); System.out.println("numebr of robots is now " + Robot.ccount); } } To fix this issue:
- Name the class and file the same.
- Make sure the example of both names is consistent.
See an example of the "Public class XXX should exist in file" mistake. (@StackOverflow)
6. "incompatible types"
"Incompatible types" is an error in logic that occurs when an assignment statement tries to pair a variable with an expression of types. It frequently comes when the code tries to place a text cord into an integer — or vice versa. This is not a Java syntax error. ( @StackOverflow )
exam.java:78: fault: incompatible types return stringBuilder.toString(); ^ required: int institute: String ane fault
In that location actually isn't an like shooting fish in a barrel ready when the compiler gives an "incompatible types" message:
- There are functions that tin convert types.
- Developer may demand to change what the lawmaking is expected to do.
Check out an case of how trying to assign a string to an integer created the "incompatible types." ( @StackOverflow )
7. "invalid method annunciation; return type required"
This Coffee software error message ways the return type of a method was not explicitly stated in the method signature.
public grade Circumvolve { private double radius; public CircleR(double r) { radius = r; } public diameter() { double d = radius * 2; render d; } } There are a few ways to trigger the "invalid method declaration; return blazon required" error:
- Forgetting to state the blazon
- If the method does non render a value and then "void" needs to be stated as the blazon in the method signature.
- Constructor names do not need to land type. But if there is an error in the constructor name, then the compiler will treat the constructor as a method without a stated blazon.
Follow an example of how constructor naming triggered the "invalid method proclamation; render type required" issue. ( @StackOverflow )
viii. "method <X> in grade <Y> cannot exist applied to given types"
This Java software error bulletin is 1 of the more helpful mistake letters. It explains how the method signature is calling the incorrect parameters.
RandomNumbers.java:9: error: method generateNumbers in course RandomNumbers cannot exist applied to given types; generateNumbers(); required: int[] found:generateNumbers(); reason: actual and formal argument lists differ in length
The method called is expecting certain arguments divers in the method's declaration. Cheque the method declaration and call carefully to make sure they are compatible.
This discussion illustrates how a Coffee software error bulletin identifies the incompatibility created by arguments in the method proclamation and method call. ( @StackOverflow )
9. "missing return statement"
The "missing return statement" message occurs when a method does non have a return statement. Each method that returns a value (a non-void type) must have a statement that literally returns that value so information technology can be called exterior the method.
public String[] OpenFile() throws IOException { Map<String, Double> map = new HashMap(); FileReader fr = new FileReader("money.txt"); BufferedReader br = new BufferedReader(fr); try{ while (br.ready()){ String str = br.readLine(); String[] listing = str.dissever(" "); System.out.println(list); } } catch (IOException e){ System.err.println("Error - IOException!"); } } In that location are a couple of reasons why a compiler throws the "missing render argument" bulletin:
- A return argument was only omitted past mistake.
- The method did not render any value but type void was not declared in the method signature.
Check out an example of how to fix the "missing return statement" Coffee software error . ( @StackOverflow )
ten. "possible loss of precision"
"Possible loss of precision" occurs when more information is assigned to a variable than it tin agree. If this happens, pieces will be thrown out. If this is fine, so the code needs to explicitly declare the variable as a new type.
A "possible loss of precision" fault commonly occurs when:
- Trying to assign a existent number to a variable with an integer data type.
- Trying to assign a double to a variable with an integer data blazon.
This explanation of Primitive Information Types in Java shows how the information is characterized. ( @Oracle )
eleven. "reached cease of file while parsing"
This fault message usually occurs in Java when the program is missing the endmost curly brace ("}"). Sometimes it can be quickly stock-still by placing it at the end of the code.
public course mod_MyMod extends BaseMod public String Version () { return "1.2_02" ; } public void AddRecipes ( CraftingManager recipes ) { recipes . addRecipe ( new ItemStack ( Item . diamond ), new Object [] { "#" , Character . valueOf ( '#' ), Block . dirt }); }
The in a higher place code results in the following error:
java : 11 : reached end of file while parsing }
Coding utilities and proper code indenting tin make it easier to find these unbalanced braces.
This example shows how missing braces can create the "reached cease of file while parsing" error message. ( @StackOverflow )
12. "unreachable statement"
"Unreachable statement" occurs when a statement is written in a place that prevents information technology from being executed. Usually, this is after a break or return statement.
for (;;){ break ; ... // unreachable argument } int i = 1 ; if ( i == 1 ) ... else ... // dead code Often simply moving the return statement will fix the error. Read the discussion of how to fix unreachable statement Coffee software error . ( @StackOverflow )
13. "variable <X> might non accept been initialized"
This occurs when a local variable declared within a method has not been initialized. Information technology can occur when a variable without an initial value is part of an if statement.
int ten ; if ( condition ) { x = 5 ; } System . out . println ( x ); // ten may not have been initialized
Read this discussion of how to avoid triggering the "variable <X> might not have been initialized" error. ( @reddit )
xiv. "Operator .. cannot exist practical to <X>"
This upshot occurs when operators are used for types, not in their definition.
operator < cannot be applied to java . lang . Object , java . lang . Object
This ofttimes happens when the Coffee code tries to use a blazon cord in a adding. To set it, the string needs to be converted to an integer or bladder.
Read this example of how non-numeric types were causing a Java software mistake warning that an operator cannot be applied to a type. ( @StackOverflow )
15. "inconvertible types"
The "inconvertible types" error occurs when the Coffee code tries to perform an illegal conversion.
TypeInvocationConversionTest . java : 12 : inconvertible types plant : java . util . ArrayList < java . lang . Class <? extends TypeInvocationConversionTest . Interface1 >> required : java . util . ArrayList < coffee . lang . Form <?>> lessRestrictiveClassList = ( ArrayList < Class <?>>) classList ; ^
For instance, booleans cannot exist converted to an integer.
Read this discussion most finding ways to convert inconvertible types in Coffee software. ( @StackOverflow )
16. "missing return value"
You'll get the "missing return value" message when the return statement includes an wrong type. For example, the post-obit code:
public grade SavingsAcc2 { private double rest ; private double interest ; public SavingsAcc2 () { residuum = 0.0 ; interest = six.17 ; } public SavingsAcc2 ( double initBalance , double interested ) { balance = initBalance ; interest = interested ; } public SavingsAcc2 deposit ( double corporeality ) { residue = balance + amount ; return ; } public SavingsAcc2 withdraw ( double amount ) { remainder = balance - amount ; render ; } public SavingsAcc2 addInterest ( double interest ) { balance = remainder * ( interest / 100 ) + balance ; return ; } public double getBalance () { return balance ; } } Returns the post-obit mistake: SavingsAcc2 . coffee : 29 : missing return value render ; ^ SavingsAcc2 . java : 35 : missing return value return ; ^ SavingsAcc2 . coffee : 41 : missing return value return ; ^ 3 errors
Commonly, in that location is a return statement that doesn't return anything.
Read this give-and-take nigh how to avoid the "missing return value" Java software error message. ( @coderanch )
17. "cannot return a value from method whose event type is void"
This Java error occurs when a void method tries to return any value, such as in the following case:
public static void move () { System . out . println ( "What do y'all want to do?" ); Scanner scan = new Scanner ( Arrangement . in ); int userMove = browse . nextInt (); return userMove ; } public static void usersMove ( String playerName , int gesture ) { int userMove = move (); if ( userMove == - 1 ) { intermission ; }
Often this is fixed by irresolute to method signature to match the type in the return statement. In this case, instances of void tin be inverse to int:
public static int move () { Organization . out . println ( "What do you desire to exercise?" ); Scanner scan = new Scanner ( Organization . in ); int userMove = scan . nextInt (); render userMove ; }
Read this discussion about how to fix the "cannot return a value from method whose result type is void" error. ( @StackOverflow )
eighteen. "non-static variable . . . cannot be referenced from a static context"
This error occurs when the compiler tries to access not-static variables from a static method ( @javinpaul ):
public class StaticTest { private int count = 0 ; public static void main (String args[]) throws IOException { count ++ ; //compiler error: non-static variable count cannot be referenced from a static context } }
To fix the "non-static variable . . . cannot be referenced from a static context" error, try these 2 things:
- Declare the variable as static in the signature.
- Check on the lawmaking equally it can create an instance of a non-static object in the static method.
Read this tutorial that explains what is the difference between static and non-static variables . ( @sitesbay )
19. "non-static method . . . cannot be referenced from a static context"
This issue occurs when the Java code tries to call a non-static method in a not-static form. Here is an example:
class Sample { private int age ; public void setAge ( int a) { age =a ; } public int getAge () { render age ; } public static void main (String args[]) { System. out .println("Age is:"+ getAge()) ; } }
Would return this fault:
Exception in thread "primary" coffee.lang.Error: Unresolved compilation problem: Cannot make a static reference to the not– static method getAge() from the type Sample
To phone call a non-static method from a static method is to declare an instance of the class calling the non-static method.
Read this explanation on what is the difference between not-static methods and static methods .
20. "(array) <X> non initialized"
Y'all'll get the "(array) <Ten> not initialized" message when an array has been declared but not initialized. Arrays are fixed in length and so each assortment needs to be initialized with the desired length.
The following lawmaking is acceptable:
AClass[] array = {object1 , object2} Every bit is: AClass[] assortment = new AClass[ 2 ] ; … array[ 0 ] = object1 ; assortment[ 1 ] = object2 ; But non: AClass[] array ; … assortment = {object1 , object2} ;
Read this discussion of how to initialize arrays in Java software . ( @StackOverflow )
Runtime Exceptions
21. "ArrayIndexOutOfBoundsException"
This is a runtime mistake message that occurs when the code attempts to access an assortment index that is not within the values. The following code would trigger this exception:
String[] name = {"tom" , "dick" , "harry"} ; for ( int i = 0 ; i<=proper name.length ; i++) { Organization.out.print(name[i] +'\n') ; } Hither's another case (@DukeU): int [] list = new int [ v ] ; list[ five ] = 33 ; // illegal alphabetize, maximum index is 4
Array indexes outset at zero and end at one less than the length of the array. Often information technology is fixed by using "<" instead of "<=" when defining the limits of the array alphabetize.
Bank check out this example on how an index triggered the "ArrayIndexOutOfBoundsException" Coffee software error bulletin . ( @StackOverflow )
22. "StringIndexOutOfBoundsException"
This is an outcome that occurs when the code attempts to access a part of the string that is not within the bounds of the string. Unremarkably, this happens when the code tries to create a substring of a string that is non of the same length equally the parameter. Here's an example ( @javacodegeeks ) :
public form StringCharAtExample { public static void primary (String[] args) { Cord str = "Java Code Geeks!" ; System. out .println("Length: " + str.length()) ; //The following statement throws an exception, because //the request alphabetize is invalid. char ch = str.charAt( fifty ) ; } }
Like array indexes, string indexes get-go at naught. When indexing a string, the last character is at 1 less than the length of the cord. The "StringIndexOutOfBoundsException" Java software mistake message unremarkably ways the index is trying to access characters that aren't there.
Hither's an instance that illustrates how the "StringIndexOutOfBoundsException" can occur and exist fixed. ( @StackOverflow )
23. "NullPointerException"
A "NullPointerException" will occur when the programme tries to utilise an object reference that does non have a value assigned to information technology ( @geeksforgeeks ).
// A Java programme to demonstrate that invoking a method // on null causes NullPointerException import java.io.* ; grade GFG { public static void main (String[] args) { // Initializing Cord variable with null value String ptr = goose egg; // Checking if ptr.equals null or works fine. try { // This line of code throws NullPointerException // because ptr is zilch if (ptr.equals("gfg")) Organisation. out .impress("Same") ; else System. out .print("Not Same") ; } catch (NullPointerException e) { System. out .print("NullPointerException Caught") ; } } }
The Java program frequently raises an exception when:
- A statement references an object with a null value.
- Trying to admission a class that is divers simply isn't assigned a reference.
Hither'south a discussion of when developers encounter the "NullPointerException" error and how to handle it. ( @StackOverflow )
24. "NoClassDefFoundError"
The "NoClassDefFoundError" will occur when the interpreter cannot find the file containing a class with the principal method. Here's an case from DZone ( @DZone ):
If y'all compile this program:
form A { // some lawmaking } public form B { public static void main (String[] args) { A a = new A() ; } }
Two .class files are generated: A.class and B.form. Removing the A.class file and running the B.class file, will become y'all the "NoClassDefFoundError":
Exception in thread "main" coffee.lang.NoClassDefFoundError: A at MainClass.main(MainClass.java: ten ) Caused past: java.lang.ClassNotFoundException: A at java.internet.URLClassLoader.findClass(URLClassLoader.coffee: 381 ) at java.lang.ClassLoader.loadClass(ClassLoader.coffee: 424 ) at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.coffee: 331 ) at java.lang.ClassLoader.loadClass(ClassLoader.java: 357 )
This can happen if:
- The file is not in the right directory.
- The name of the class is not the same as the proper noun of the file (without the file extension). Likewise, the names are case sensitive.
Read this discussion of why "NoClassDefFoundError" occurs when running Coffee software . ( @StackOverflow )
25. "NoSuchMethodFoundError"
This error message volition occur when the Java software tries to phone call a method of a grade and the method no longer has a definition ( @myUND ):
Error: Could not find or load master class wiki.coffee
Often the "NoSuchMethodFoundError" Java software error occurs when in that location is a typo in the proclamation.
Read this tutorial to learn how to avoid the fault bulletin "NoSuchMethodFoundError ". ( @javacodegeeks )
26. "NoSuchProviderException"
"NoSuchProviderException" occurs when a security provider is requested that is not available ( @alvinalexander ):
javax.post.NoSuchProviderException
When trying to discover why "NoSuchProviderException" occurs, bank check:
- The JRE configuration.
- The Java_home is set in the configuration.
- The Java environment being used.
- The security provider entry.
Read this give-and-take of what causes "NoSuchProviderException" when you run Java software. ( @StackOverflow )
27. AccessControlException
"AccessControlException" indicates that requested access to arrangement resources such as a file organization or network is denied, as in this instance from JBossDeveloper ( @jbossdeveloper ):
ERROR Could not annals mbeans java.security. AccessControlException: WFSM000001: Permission check failed (permission "("javax.management.MBeanPermission" "org.apache.logging.log4j.core.jmx.LoggerContextAdmin#- [org.apache.logging.log4j2:type= 51634f ]" "registerMBean")" in code source "(vfs:/C:/wildfly- ten.0.0 .Terminal/standalone/deployments/mySampleSecurityApp.war/Web-INF/lib/log4j-core- 2.v . jar )" of " null ")
Read this discussion of a workaround used to get past an "AccessControlException" fault. ( @github )
28. "ArrayStoreException"
An "ArrayStoreException" occurs when the rules of casting elements in Java arrays are broken. Exist very careful nearly what values you place inside an assortment. ( @Roedyg ) For case, this example from JavaScan.com illustrates that this program ( @java_scan ):
/* …………… START …………… */ public grade JavaArrayStoreException { public static void main (String… args) { Object[] val = new Integer[ 4 ] ; val[ 0 ] = v.8 ; } } /* …………… End …………… */
Results in the following output:
Exception in thread "main" java.lang.ArrayStoreException: java.lang.Double at ExceptionHandling.JavaArrayStoreException.main(JavaArrayStoreException.java: seven )
When an array is initialized, the sorts of objects allowed into the assortment need to exist declared. And so each array element needs to exist of the same blazon of object.
Read this give-and-take of how to solve for the "ArrayStoreException". ( @StackOverflow )
29. "bad magic number"
This Java software error message means something may be wrong with the class definition files on the network. Here's an case from The Server Side ( @TSS_dotcom ):
Java(TM) Plug–in: Version 1.3.1_01 Using JRE version i.3.1_01 Coffee HotSpot(TM) Customer VM User dwelling directory = C:\Documents and Settings\Ankur Proxy Configuration: Manual Configuration Proxy: 192.168.11.half-dozen : fourscore coffee.lang.ClassFormatError: SalesCalculatorAppletBeanInfo (Bad magic number) at java.lang.ClassLoader.defineClass0(Native Method) at java.lang.ClassLoader.defineClass(Unknown Source) at java.security.SecureClassLoader.defineClass(Unknown Source) at sun.applet.AppletClassLoader.findClass(Unknown Source) at sun.plugin.security.PluginClassLoader.access$201(Unknown Source) at sun.plugin.security.PluginClassLoader$1.run(Unknown Source) at coffee.security.AccessController.doPrivileged(Native Method) at lord's day.plugin.security.PluginClassLoader.findClass(Unknown Source) at java.lang.ClassLoader.loadClass(Unknown Source) at sun.applet.AppletClassLoader.loadClass(Unknown Source) at java.lang.ClassLoader.loadClass(Unknown Source) at java.beans.Introspector.instantiate(Unknown Source) at java.beans.Introspector.findInformant(Unknown Source) at coffee.beans.Introspector.(Unknown Source) at java.beans.Introspector.getBeanInfo(Unknown Source) at lord's day.beans.ole.OleBeanInfo.(Unknown Source) at dominicus.beans.ole.StubInformation.getStub(Unknown Source) at sun.plugin.ocx.TypeLibManager$1.run(Unknown Source) at java.security.AccessController.doPrivileged(Native Method) at sun.plugin.ocx.TypeLibManager.getTypeLib(Unknown Source) at lord's day.plugin.ocx.TypeLibManager.getTypeLib(Unknown Source) at sunday.plugin.ocx.ActiveXAppletViewer.statusNotification(Native Method) at sun.plugin.ocx.ActiveXAppletViewer.notifyStatus(Unknown Source) at sun.plugin.ocx.ActiveXAppletViewer.showAppletStatus(Unknown Source) at sunday.applet.AppletPanel.run(Unknown Source) at java.lang.Thread.run(Unknown Source)
The "bad magic number" error bulletin happens when:
- The offset four bytes of a class file is not the hexadecimal number CAFEBABE.
- The class file was uploaded every bit in ASCII fashion, not binary mode.
- The java plan is run before it is compiled.
Read this discussion of how to find the reason for a "bad magic number". ( @coderanch )
thirty. "cleaved pipe"
This fault message refers to the data stream from a file or network socket that has stopped working or is closed from the other end ( @ExpertsExchange ).
Exception in thread "main" java.net.SocketException: Cleaved pipe at java.net.SocketOutputStream.socketWrite0(Native Method) at coffee.net.SocketOutputStream.socketWrite(SocketOutputStream.coffee: 92 ) at java.net.SocketOutputStream.write(SocketOutputStream.java: 115 ) at java.io.DataOutputStream.write
The causes of a "broken pipe" error often include:
- Running out of disk scratch space.
- RAM may be clogged.
- The data stream may exist corrupt.
- The process of reading the pipe might have been airtight.
Read this give-and-take of what is the Java error "broken piping" . ( @StackOverflow )
31. "could not create Coffee Virtual Machine"
This Java error bulletin unremarkably occurs when the code tries to invoke Java with the wrong arguments (@ghacksnews):
Error: Could not create the Java Virtual Machine Error: A fatal exception has occurred. Program will get out.
It often is caused by a mistake in the declaration in the lawmaking or allocating the proper amount of memory to it.
Read this give-and-take of how to fix the Coffee software fault "Could not create Java Virtual Machine" . ( @StackOverflow )
32. "class file contains incorrect course"
The "class file contains wrong course" effect occurs when the Coffee code tries to find the course file in the wrong directory, resulting in an mistake message similar to the following:
MyTest.java: x : cannot access MyStruct bad class file: D:\Java\test\MyStruct.java file does not contain class MyStruct Delight remove or make certain it appears in the correct subdirectory of the classpath. MyStruct ms = new MyStruct() ; ^
To fix this error, these tips should help:
- Make sure the name of the source file and the name of the course match — including the text case.
- Check if the bundle statement is correct or missing.
- Make certain the source file is in the right directory.
Read this discussion of how to fix a "class file contains incorrect class" error. ( @StackOverflow )
33. "ClassCastException"
The "ClassCastException" bulletin indicates the Java code is trying to cast an object to the wrong class. Hither is an example from Java Concept of the Day:
package com ; grade A { int i = 10 ; } course B extends A { int j = 20 ; } form C extends B { int k = 30 ; } public course ClassCastExceptionDemo { public static void main (String[] args) { A a = new B() ; //B blazon is auto upwards casted to A blazon B b = (B) a ; //A blazon is explicitly down casted to B blazon. C c = (C) b ; //Here, yous will become class cast exception System. out .println(c. k ) ; } }
Results in this error:
Exception in thread "main" coffee.lang.ClassCastException: com.B cannot be bandage to com.C at com.ClassCastExceptionDemo.main(ClassCastExceptionDemo.java: 23 )
The Java code will create a bureaucracy of classes and subclasses. To avoid the "ClassCastException" mistake, make sure the new type belongs to the right course or one of its parent classes. If Generics are used, these errors tin can be defenseless when the lawmaking is compiled.
Read this tutorial on how to fix "ClassCastException" Coffee software errors . ( @java_concept )
34. "ClassFormatError"
The "ClassFormatError" message indicates a linkage error and occurs when a class file cannot exist read or interpreted equally a form file.
Caused past: coffee.lang.ClassFormatError: Absent-minded Lawmaking attribute in method that is not native or abstruse in course file javax/persistence/GenerationType at java.lang.ClassLoader.defineClass1(Native Method) at java.lang.ClassLoader.defineClassCond(Unknown Source) at java.lang.ClassLoader.defineClass(Unknown Source) at java.security.SecureClassLoader.defineClass(Unknown Source) at coffee.cyberspace.URLClassLoader.defineClass(Unknown Source) at coffee.net.URLClassLoader.access$000(Unknown Source) at coffee.net.URLClassLoader$1.run(Unknown Source) at java.security.AccessController.doPrivileged(Native Method) at java.net.URLClassLoader.findClass(Unknown Source) at java.lang.ClassLoader.loadClass(Unknown Source) at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source) at java.lang.ClassLoader.loadClass(Unknown Source)
There are several reasons why a "ClassFormatError" tin can occur:
- The class file was uploaded as in ASCII mode not binary mode.
- The web server must send class files as binary, non ASCII.
- At that place could be a classpath error that prevents the code from finding the class file.
- If the class is loaded twice, the second fourth dimension volition throw an exception.
- Yous're using an old version of Coffee runtime.
Read this discussion nigh what causes the "ClassFormatError" in Java. ( @StackOverflow )
35. "ClassNotFoundException"
"ClassNotFoundException" but occurs at run time — meaning a class that was there during compilation is missing at run fourth dimension. This is a linkage error.
Much similar the "NoClassDefFoundError" this issue can occur if:
- The file is not in the right directory.
- The proper name of the grade is not the aforementioned as the proper noun of the file (without the file extension). Besides, the names are case-sensitive.
Read this word of what causes "ClassNotFoundException" for more than cases. ( @StackOverflow )
36. "ExceptionInInitializerError"
This Java issue will occur when something goes incorrect with a static initialization ( @GitHub ). When the Java code later uses the class, the "NoClassDefFoundError" mistake will occur.
java.lang.ExceptionInInitializerError at org.eclipse.mat.hprof.HprofIndexBuilder.fill(HprofIndexBuilder.java: 54 ) at org.eclipse.mat.parser.internal.SnapshotFactory.parse(SnapshotFactory.java: 193 ) at org.eclipse.mat.parser.internal.SnapshotFactory.openSnapshot(SnapshotFactory.coffee: 106 ) at com.squareup.leakcanary.HeapAnalyzer.openSnapshot(HeapAnalyzer.java: 134 ) at com.squareup.leakcanary.HeapAnalyzer.checkForLeak(HeapAnalyzer.coffee: 87 ) at com.squareup.leakcanary.internal.HeapAnalyzerService.onHandleIntent(HeapAnalyzerService.java: 56 ) at android.app.IntentService$ServiceHandler.handleMessage(IntentService.coffee: 65 ) at android.os.Handler.dispatchMessage(Handler.java: 102 ) at android.os.Looper.loop(Looper.java: 145 ) at android.os.HandlerThread.run(HandlerThread.java: 61 ) Caused past: java.lang.NullPointerException: in == null at coffee.util.Properties.load(Properties.java: 246 ) at org.eclipse.mat.util.MessageUtil.(MessageUtil.java: 28 ) at org.eclipse.mat.util.MessageUtil.(MessageUtil.java: 13 ) … 10 more
There needs to be more information to set up the error. Using getCause() in the code can return the exception that caused the error to exist returned.
Read this discussion about how to track downwardly the crusade of the "ExceptionInInitializerError ". ( @StackOverflow )
37. "IllegalBlockSizeException"
An "IllegalBlockSizeException" will occur during decryption when the length message is not a multiple of eight bytes. Here'southward an example from ProgramCreek.com (@ProgramCreek):
@Override protected byte [] engineWrap(Cardinal key) throws IllegalBlockSizeException , InvalidKeyException { effort { byte [] encoded = key.getEncoded() ; return engineDoFinal(encoded , 0 , encoded.length) ; } grab (BadPaddingException e) { IllegalBlockSizeException newE = new IllegalBlockSizeException() ; newE.initCause(e) ; throw newE ; } }
The "IllegalBlockSizeException" could exist caused by:
- Using dissimilar encryption and decryption algorithm options.
- Truncating or garbling the decrypted message during transmission.
Read this discussion nearly how to forbid the "IllegalBlockSizeException " Coffee software error message. ( @StackOverflow )
38. "BadPaddingException"
A "BadPaddingException" will occur during decryption when padding was used to create a message that can be measured by a multiple of 8 bytes. Here'southward an example from Stack Overflow ( @StackOverflow ):
javax.crypto.BadPaddingException: Given final block not properly padded at com.sun.crypto.provider.SunJCE_f.b(DashoA13*..) at com.lord's day.crypto.provider.SunJCE_f.b(DashoA13*..) at com.sun.crypto.provider.AESCipher.engineDoFinal(DashoA13*..) at javax.crypto.Cipher.doFinal(DashoA13*..)
Encrypted information is binary and so don't try to store it in a string or the data will not be padded properly during encryption.
Read this discussion about how to prevent the "BadPaddingException ". ( @StackOverflow )
39. "IncompatibleClassChangeError"
An "IncompatibleClassChangeError" is a form of LinkageError that tin occur when a base course changes after the compilation of a child class. This case is from How to Practise in Java ( @HowToDoInJava ):
Exception in thread "main" java.lang.IncompatibleClassChangeError: Implementing class
at java.lang.ClassLoader.defineClass1(Native Method) at java.lang.ClassLoader.defineClass(Unknown Source) at java.security.SecureClassLoader.defineClass(Unknown Source) at coffee.net.URLClassLoader.defineClass(Unknown Source) at coffee.net.URLClassLoader.access$000(Unknown Source) at coffee.net.URLClassLoader$i.run(Unknown Source) at java.security.AccessController.doPrivileged(Native Method) at coffee.cyberspace.URLClassLoader.findClass(Unknown Source) at java.lang.ClassLoader.loadClass(Unknown Source) at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source) at java.lang.ClassLoader.loadClass(Unknown Source) at java.lang.ClassLoader.loadClassInternal(Unknown Source) at internet.sf.cglib.core.DebuggingClassWriter.toByteArray(DebuggingClassWriter.java: 73 ) at internet.sf.cglib.core.DefaultGeneratorStrategy.generate(DefaultGeneratorStrategy.java: 26 ) at net.sf.cglib.core.AbstractClassGenerator.create(AbstractClassGenerator.java: 216 ) at net.sf.cglib.cadre.KeyFactory$Generator.create(KeyFactory.java: 144 ) at net.sf.cglib.cadre.KeyFactory.create(KeyFactory.java: 116 ) at cyberspace.sf.cglib.cadre.KeyFactory.create(KeyFactory.java: 108 ) at net.sf.cglib.cadre.KeyFactory.create(KeyFactory.java: 104 ) at net.sf.cglib.proxy.Enhancer.(Enhancer.java: 69 )
When the "IncompatibleClassChangeError" occurs, it is possible that:
- The static on the main method was forgotten.
- A legal class was used illegally.
- A class was changed and there are references to it from another form past its sometime signatures.
Try deleting all grade files and recompiling everything, or effort these steps to resolve the "IncompatibleClassChangeError" . ( @javacodegeeks )
40. "FileNotFoundException"
This Coffee software error bulletin is thrown when a file with the specified pathname does not exist.
@Override public ParcelFileDescriptor openFile(Uri uri , String style) throws FileNotFoundException { if (uri.toString().startsWith(FILE_PROVIDER_PREFIX)) { int 1000=ParcelFileDescriptor.MODE_READ_ONLY ; if (mode.equalsIgnoreCase("rw")) m=ParcelFileDescriptor.MODE_READ_WRITE ; File f= new File(uri.getPath()) ; ParcelFileDescriptor pfd=ParcelFileDescriptor. open up (f , g) ; return pfd ; } else { throw new FileNotFoundException("Unsupported uri: " + uri.toString()) ; } }
In addition to files non exhibiting the specified pathname, this could mean the existing file is inaccessible.
Read this discussion well-nigh why the "FileNotFoundException" could be thrown . ( @StackOverflow )
41. "EOFException"
An "EOFException" is thrown when an cease of file or end of the stream has been reached unexpectedly during input. Here's an example from JavaBeat of an application that throws an EOFException:
import java.io.DataInputStream ; import java.io.EOFException ; import java.io.File ; import coffee.io.FileInputStream ; import java.io.IOException ; public grade ExceptionExample { public void testMethod1 (){ File file = new File("test.txt") ; DataInputStream dataInputStream = goose egg; try { dataInputStream = new DataInputStream( new FileInputStream(file)) ; while ( true ){ dataInputStream.readInt() ; } } take hold of (EOFException e){ e.printStackTrace() ; } grab (IOException e){ e.printStackTrace() ; } finally { try { if (dataInputStream != null ){ dataInputStream.shut() ; } } catch (IOException east){ e.printStackTrace() ; } } } public static void main (String[] args){ ExceptionExample instance1 = new ExceptionExample() ; instance1.testMethod1() ; } }
Running the program above results in the post-obit exception:
coffee.io.EOFException at java.io.DataInputStream.readInt(DataInputStream.coffee: 392 ) at logging.elementary.ExceptionExample.testMethod1(ExceptionExample.java: 16 ) at logging.simple.ExceptionExample.primary(ExceptionExample.java: 36 )
When there is no more data while the class "DataInputStream" is trying to read data in the stream, "EOFException" will be thrown. It tin can besides occur in the "ObjectInputStream" and "RandomAccessFile" classes.
Read this discussion nearly when the "EOFException" tin occur while running Java software . ( @StackOverflow )
42. "UnsupportedEncodingException"
This Coffee software error bulletin is thrown when the grapheme encoding is non supported ( @Penn ).
public UnsupportedEncodingException()
Information technology is possible that the Java Virtual Machine being used doesn't support a given character set.
Read this discussion of how to handle "UnsupportedEncodingException" while running Java software. ( @StackOverflow )
43. "SocketException"
A "SocketException" message indicates at that place is an error creating or accessing a socket (@ProgramCreek).
public void init(Cord contextName , ContextFactory manufactory) { super .init(contextName , factory) ; String periodStr = getAttribute(PERIOD_PROPERTY) ; if (periodStr != naught ) { int period = 0 ; try { period = Integer.parseInt(periodStr) ; } grab (NumberFormatException nfe) { } if (menstruation <= 0 ) { throw new MetricsException("Invalid period: " + periodStr) ; } setPeriod(period) ; } metricsServers = Util.parse(getAttribute(SERVERS_PROPERTY) , DEFAULT_PORT) ; unitsTable = getAttributeTable(UNITS_PROPERTY) ; slopeTable = getAttributeTable(SLOPE_PROPERTY) ; tmaxTable = getAttributeTable(TMAX_PROPERTY) ; dmaxTable = getAttributeTable(DMAX_PROPERTY) ; try { datagramSocket = new DatagramSocket() ; } catch (SocketException se) { se.printStackTrace() ; } }
This exception usually is thrown when the maximum connections are reached due to:
- No more network ports bachelor to the awarding.
- The arrangement doesn't have enough memory to back up new connections.
Read this discussion of how to resolve "SocketException" issues while running Java software. ( @StackOverflow )
44. "SSLException"
This Java software error message occurs when there is failure in SSL-related operations. The following case is from Atlassian ( @Atlassian ):
com.dominicus.jersey.api.customer.ClientHandlerException: javax.net.ssl.SSLException: java.lang.RuntimeException: Unexpected mistake: coffee.security.InvalidAlgorithmParameterException: the trustAnchors parameter must be non–empty at com.sun.jersey.customer.apache.ApacheHttpClientHandler.handle(ApacheHttpClientHandler.coffee: 202 ) at com.sun.jersey.api.client.Customer.handle(Client.java: 365 ) at com.lord's day.jersey.api.client.WebResource.handle(WebResource.java: 556 ) at com.sunday.jersey.api.client.WebResource.get(WebResource.java: 178 ) at com.atlassian.plugins.client.service.product.ProductServiceClientImpl.getProductVersionsAfterVersion(ProductServiceClientImpl.coffee: 82 ) at com.atlassian.upm.pac.PacClientImpl.getProductUpgrades(PacClientImpl.java: 111 ) at com.atlassian.upm.residual.resource.ProductUpgradesResource.go(ProductUpgradesResource.java: 39 ) at dominicus.reverberate.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) at sun.reverberate.DelegatingMethodAccessorImpl.invoke(Unknown Source) at java.lang.reverberate.Method.invoke(Unknown Source) at com.atlassian.plugins.rest.common.interceptor.impl.DispatchProviderHelper$ResponseOutInvoker$1.invoke(DispatchProviderHelper.java: 206 ) at com.atlassian.plugins.rest.mutual.interceptor.impl.DispatchProviderHelper$1.intercept(DispatchProviderHelper.java: 90 ) at com.atlassian.plugins.rest.common.interceptor.impl.DefaultMethodInvocation.invoke(DefaultMethodInvocation.coffee: 61 ) at com.atlassian.plugins.rest.common.expand.interceptor.ExpandInterceptor.intercept(ExpandInterceptor.java: 38 ) at com.atlassian.plugins.remainder.mutual.interceptor.impl.DefaultMethodInvocation.invoke(DefaultMethodInvocation.coffee: 61 ) at com.atlassian.plugins.residue.mutual.interceptor.impl.DispatchProviderHelper.invokeMethodWithInterceptors(DispatchProviderHelper.java: 98 ) at com.atlassian.plugins.remainder.mutual.interceptor.impl.DispatchProviderHelper.access$100(DispatchProviderHelper.java: 28 ) at com.atlassian.plugins.residuum.mutual.interceptor.impl.DispatchProviderHelper$ResponseOutInvoker._dispatch(DispatchProviderHelper.java: 202 ) … Caused by: javax.net.ssl.SSLException: java.lang.RuntimeException: Unexpected error: coffee.security.InvalidAlgorithmParameterException: the trustAnchors parameter must be non–empty … Acquired by: java.lang.RuntimeException: Unexpected error: coffee.security.InvalidAlgorithmParameterException: the trustAnchors parameter must be non–empty … Acquired by: java.security.InvalidAlgorithmParameterException: the trustAnchors parameter must be non–empty
This can happen if:
- Certificates on the server or client take expired.
- A server port has been reset to some other port.
Read this discussion of what can crusade the "SSLException" error in Java software. ( @StackOverflow )
45. "MissingResourceException"
A "MissingResourceException" occurs when a resource is missing. If the resource is in the right classpath, this is ordinarily because a properties file is not configured properly. Hither'due south an instance ( @TIBCO ):
java.util.MissingResourceException: Can't notice bundle for base of operations name localemsgs_en_US , locale en_US java.util.ResourceBundle.throwMissingResourceException java.util.ResourceBundle.getBundleImpl java.util.ResourceBundle.getBundle net.sf.jasperreports.engine.util.JRResourcesUtil.loadResourceBundle cyberspace.sf.jasperreports.engine.util.JRResourcesUtil.loadResourceBundle
Read this discussion of how to gear up "MissingResourceException" while running Coffee software.
46. "NoInitialContextException"
A "NoInitialContextException" error occurs when the Java awarding wants to perform a naming operation merely can't create a connection ( @TheASF ).
[java] Caused by: javax.naming.NoInitialContextException: Need to specify grade proper noun in environs or organization property , or as an applet parameter , or in an application resource file: java.naming.manufacturing plant.initial [java] at javax.naming.spi.NamingManager.getInitialContext(NamingManager.java: 645 ) [java] at javax.naming.InitialContext.getDefaultInitCtx(InitialContext.java: 247 ) [java] at javax.naming.InitialContext.getURLOrDefaultInitCtx(InitialContext.java: 284 ) [java] at javax.naming.InitialContext.lookup(InitialContext.java: 351 ) [java] at org.apache.camel.impl.JndiRegistry.lookup(JndiRegistry.java: 51 )
This can be a complex problem to solve only here are some possible bug that cause the "NoInitialContextException" Java error message:
- The application may not take the proper credentials to make a connexion.
- The lawmaking may not place the implementation of JNDI needed.
- The "InitialContext" class may not exist configured with the correct properties.
Read this discussion of what "NoInitialContextException" means when running Java software. ( @StackOverflow )
47. "NoSuchElementException"
A "NoSuchElementException" error happens when an iteration (such equally a "for" loop) tries to access the next element when there is none.
public class NoSuchElementExceptionDemo{ public static void master (String args[]) { Hashtable sampleMap = new Hashtable() ; Enumeration enumeration = sampleMap.elements() ; enumeration.nextElement() ; //java.util.NoSuchElementExcepiton hither because enumeration is empty } } Output: Exception in thread "primary" java.util.NoSuchElementException: Hashtable Enumerator at java.util.Hashtable$EmptyEnumerator.nextElement(Hashtable.java: 1084 ) at exam.ExceptionTest.main(NoSuchElementExceptionDemo.java: 23 )
The "NoSuchElementException" can exist thrown past these methods:
- Enumeration::nextElement()
- NamingEnumeration::adjacent()
- StringTokenizer::nextElement()
- Iterator::next()
Read this tutorial on how to fix "NoSuchElementException" in Coffee software. ( @javinpaul )
48. "NoSuchFieldError"
This Java software error message is thrown when an application tries to access a field in an object simply the specified field no longer exists in the object ( @sourceforge ).
public NoSuchFieldError()
Commonly, this error is caught in the compiler merely will exist defenseless during runtime if a form definition has been changed betwixt compiling and running.
Read this give-and-take of how to notice what causes the "NoSuchFieldError" when running Java software. @StackOverflow
49. "NumberFormatException"
This Java software error message occurs when the awarding tries to convert a string to a numeric type, just that the number is non a valid string of digits ( @alvinalexander ).
bundle com.devdaily.javasamples ; public class ConvertStringToNumber { public static void main (String[] args) { effort { String due south = "FOOBAR" ; int i = Integer. parseInt (s) ; // this line of code will never be reached Arrangement. out .println(" int value = " + i) ; } catch (NumberFormatException nfe) { nfe.printStackTrace() ; } } }
The mistake "NumberFormatException" is thrown when:
- Leading or trailing spaces in the number exist.
- The sign is not ahead of the number.
- The number has commas.
- Localisation may non categorize it as a valid number.
- The number is too big to fit in the numeric type.
Read this discussion of how to avoid "NumberFormatException" when running Java software. ( @StackOverflow )
50. "TimeoutException"
This Java software error bulletin occurs when a blocking functioning is timed out .
individual void queueObject(ComplexDataObject obj) throws TimeoutException , InterruptedException { if (!queue.offer(obj , 10 , TimeUnit.SECONDS)) { TimeoutException ex= new TimeoutException("Timed out waiting for parsed elements to exist candy. Aborting.") ; throw ex ; } }
Read this discussion near how to handle "TimeoutException" when running Java software. ( @StackOverflow )
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