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Error: Could not find or load main class InputAddress; Caused by: java.lang.NoClassDefFoundError: inputaddress/InputAddress (wrong name: <filename> ) [duplicate]

I wrote a java program to test RESTful web services by using Netbeans7.0.1 and it works fine there. Now I wrote the build.xml file to compile the code and when I try to run the generated .class file I always got this exception:
Exception in thread "main" java.lang.NoClassDefFoundError: ClientREST (wrong name: clientrest/ClientREST)
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClassCond(ClassLoader.java:632)
at java.lang.ClassLoader.defineClass(ClassLoader.java:616)
at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:141)
at java.net.URLClassLoader.defineClass(URLClassLoader.java:283)
at java.net.URLClassLoader.access$000(URLClassLoader.java:58)
at java.net.URLClassLoader$1.run(URLClassLoader.java:197)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
at java.lang.ClassLoader.loadClass(ClassLoader.java:307)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301)
at java.lang.ClassLoader.loadClass(ClassLoader.java:248)
Could not find the main class: ClientREST. Program will exit.
The name and path are correct, so any thoughts why I'm getting this exception?

Exception in thread "main" java.lang.NoClassDefFoundError: ClientREST
So, you ran it as java ClientREST. It's expecting a ClientREST.class without any package.
(wrong name: clientrest/ClientREST)
Hey, the class is trying to tell you that it has a package clientrest;. You need to run it from the package root on. Go one folder up so that you're in the folder which in turn contains the clientrest folder representing the package and then execute java clientrest.ClientREST.
You should not go inside the clientrest package folder and execute java ClientREST.

I encountered this error using command line java:
java -cp stuff/src/mypackage Test
where Test.java resides in the package mypackage.
Instead, you need to set the classpath -cp to the base folder, in this case, src, then prepend the package to the file name.
So it will end up looking like this:
java -cp stuff/src mypackage.Test

To further note on Garry's reply: The class path is the base directory where the class itself resides. So if the class file is here -
/home/person/javastuff/classes/package1/subpackage/javaThing.class
You would need to reference the class path as follows:
/home/person/javastuff/classes
So to run from the command line, the full command would be -
java -cp /home/person/javastuff/classes package1/subpackage/javaThing
i.e. the template for the above is
java_executable -cp classpath the_class_itself_within_the_class_path
That's how I finally got mine to work without having the class path in the environment

Probably the location you are generating your classes in doesnt exists on the class path. While running use the jvm arg -verbose while running and check the log whether the class is being loaded or not.
The output will also give you clue as to where the clasess are being loaded from, make sure that your class files are present in that location.

Try the below syntax:
Suppose java File resides here: fm/src/com/gsd/FileName.java
So you can run using the below syntax:
(Make current directory to 'fm')
java src.com.gsd.FileName

Suppose you have class A
and a class B
public class A{
public static void main(String[] args){
....
.....
//creating classB object
new classB();
}
}
class B{
}
this issue can be resolved by moving class B inside of class A and using static keyword
public class A{
public static void main(String[] args){
....
.....
//creating class B
new classB();
static class B{
}
}

Here is my class structure
package org.handson.basics;
public class WithoutMain {
public static void main() {
System.out.println("With main()...");
}
}
To compile this program, I had to use absolute path. So from src/main/java I ran:
javac org/handson/basics/WithoutMain.java
Initially I tried with the below command from basics folder and it didn't work
basics % java WithoutMain
Error: Could not find or load main class WithoutMain
Caused by: java.lang.NoClassDefFoundError: org/handson/basics/WithoutMain (wrong name: WithoutMain)
Later I went back to src\main\java folder and ran the class with relevant package structure, which worked as expected.
java % java org.handson.basics.WithoutMain
With main()...

I also have encountered this error on Windows when using Class.forName() where the class name I use is correct except for case.
My guess is that Java is able to find the file at the path (because Windows paths are case-insensitive) but the parsed class's name does not match the name given to Class.forName().
Fixing the case in the class name argument fixed the error.

Executing Sample Flink Program in Local

I am trying to execute a sample program in Apache Flink in local mode.
import org.apache.flink.api.common.functions.FlatMapFunction;
import org.apache.flink.api.java.DataSet;
import org.apache.flink.api.java.ExecutionEnvironment;
import org.apache.flink.api.java.tuple.Tuple2;
import org.apache.flink.util.Collector;
public class WordCountExample {
public static void main(String[] args) throws Exception {
final ExecutionEnvironment env = ExecutionEnvironment.getExecutionEnvironment();
DataSet<String> text = env.fromElements(
"Who's there?",
"I think I hear them. Stand, ho! Who's there?");
//DataSet<String> text1 = env.readTextFile(args[0]);
DataSet<Tuple2<String, Integer>> wordCounts = text
.flatMap(new LineSplitter())
.groupBy(0)
.sum(1);
wordCounts.print();
env.execute();
env.execute("Word Count Example");
}
public static class LineSplitter implements FlatMapFunction<String, Tuple2<String, Integer>> {
#Override
public void flatMap(String line, Collector<Tuple2<String, Integer>> out) {
for (String word : line.split(" ")) {
out.collect(new Tuple2<String, Integer>(word, 1));
}
}
}
}
It is giving me exception :
Exception in thread "main" java.lang.NoClassDefFoundError: org/apache/hadoop/mapreduce/InputFormat
at WordCountExample.main(WordCountExample.java:10)
Caused by: java.lang.ClassNotFoundException: org.apache.hadoop.mapreduce.InputFormat
at java.net.URLClassLoader$1.run(URLClassLoader.java:366)
at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
at java.lang.ClassLoader.loadClass(ClassLoader.java:425)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
at java.lang.ClassLoader.loadClass(ClassLoader.java:358)
... 1 more
What am I doing wrong?
I have used the correct jars also.
flink-java-0.9.0-milestone-1.jar
flink-clients-0.9.0-milestone-1.jar
flink-core-0.9.0-milestone-1.jar

Adding the three Flink Jar files as dependencies in your project is not enough because they have other transitive dependencies, for example on Hadoop.
The easiest way to get a working setup to develop (and locally execute) Flink programs is to follow the quickstart guide which uses a Maven archetype to configure a Maven project. This Maven project can be imported into your IDE.

NoClassDefFoundError extends LinkageError
Thrown if the Java Virtual Machine or a ClassLoader instance tries to
load in the definition of a class (as part of a normal method call or
as part of creating a new instance using the new expression) and no
definition of the class could be found. The searched-for class
definition existed when the currently executing class was compiled,
but the definition can no longer be found.
Your code/jar dependent to hadoop. Found it here download jar file and add it in your classpath org.apache.hadoop.mapreduce.InputFormat

Firstly, the flink jar files which you have included in your project are not enough, include all the jar files which are present in the lib folder present under the flink's source folder.
Secondly, " env.execute();
env.execute("Word Count Example");" These lines of code are not required since you are just printing your dataset onto the console; you're not writing the output into a file(.txt, .csv etc.). So, better to remove these lines (Sometimes throws errors if included in code if not required (observed a lot of times))
Thirdly, while exporting the jar files for your Java Project from your IDE, don't forget to select your 'Main' class.
Hopefully, after making the above changes, your code works.

Workaround for java.lang.UnsupportedClassVersionError to not show it

After migration to Java 8, my tool throw the follwing exception if somebody try to run it on earlier Java environments.
Exception in thread "main" java.lang.UnsupportedClassVersionError: com/myapp/MyTool: Unsupported major.minor version 52.0
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClass(ClassLoader.java:800)
at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
at java.net.URLClassLoader.defineClass(URLClassLoader.java:449)
at java.net.URLClassLoader.access$100(URLClassLoader.java:71)
at java.net.URLClassLoader$1.run(URLClassLoader.java:361)
at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
at java.lang.ClassLoader.loadClass(ClassLoader.java:425)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
at java.lang.ClassLoader.loadClass(ClassLoader.java:358)
at sun.launcher.LauncherHelper.checkAndLoadMain(LauncherHelper.java:482)
Is there some way to not show this error, and show nice error message with proposition to upgrade Java.
As I understood I should create some small class like:
public class CheckerJavaVersion {
public static void main(String args[]) {
String sVersion = System.getProperty("java.version");
sVersion = sVersion.substring(0, 3);
Float f = Float.valueOf(sVersion);
if (f.floatValue() < (float) 1.8) {
System.out.println("Please upgrate your Java to 1.8 version");
System.exit(1);
}
}
}
and compile it via older compiler. I need some solution how to run this class firstly before the main method of MyToll class starts.
PS. Aplication is packed in jar.

The problem is that the error occurs when the class is loaded, so you'd either have to use a "starter app" which starts the actual application in a separate process or dynamically load the application after the Java version has been checked.
I didn't test it but what might work is something like this:
public static void main(String args[]) {
if( javaVersionOk ) {
Class.forName("actual.mainclass.name").getMethod("actual.main.method.name").invoke();
}
}
The idea is to access the class via its name and thus make the runtime load and initialize it at that time. I'm not sure, however, if you can delay class loading like that in all cases so you'd have to go on from there.
And btw, IIRC there already are applications/libraries that provide this kind of functionality, I just don't rember their names. So a search might be worth your while.
Edit: you might want to have a look at appstart if not for using it then for inspiration.
Another launcher would be Apache Commons Launcher.
Alternatives:
Alternatively you could just provide a launch script for each platform you want to support , call java -version and check the returned version before launching the application.
Another alternative would be to use JNLP/WebStart locally, which allows you to specify a minimum version and which AFAIK even provides for download/upgrade functionality.

problems separating class and source files

In my _Mathematics package. I've separated the source files into bin and src folders like so:
_Mathematics ->
Formulas ->
src ->
// source files containing mathematical formulas...
// Factorial.java
bin ->
// Factorial.class
// class files containing mathematical formulas...
Problems ->
src ->
// Permutation.java
// source files containing mathematical problems...
bin ->
// Permutation.class
// class files containing mathematical problems...
But, when I compile the file with main(), there is an error like so:
Exception in thread "main" java.lang.NoClassDefFoundError: _Mathematics\Problems
\bin\Permutations (wrong name: _Mathematics/Problems/bin/Permutations)
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClass(ClassLoader.java:792)
at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
at java.net.URLClassLoader.defineClass(URLClassLoader.java:449)
at java.net.URLClassLoader.access$100(URLClassLoader.java:71)
at java.net.URLClassLoader$1.run(URLClassLoader.java:361)
at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
at sun.launcher.LauncherHelper.checkAndLoadMain(LauncherHelper.java:482)
Here's the Permutation.java file, where main() is located.
package _Mathematics.Problems.bin;
import _Mathematics.Formulas.bin.Factorial;
public class Permutations {
public static void main(String args[]) {
System.out.printf("There are 10 students. Five are to be chosen and seated in a row for a picture.%nHow many linear arrangements are possible?%n" +
(new Factorial(10).r/new Factorial(5).r) + "%n%n");
System.out.printf("How many permutations are there in the word 'permutation'?%n" +
new Factorial(11).r + "%n%n");
}
}
And here is the other file I have, Factorial.java:
package _Mathematics.Formulas.bin;
public class Factorial {
public int o;
public long r;
public Factorial(int num) {
long result = 1;
for(int i = num; i > 0; i--)
result *= i;
this.o = num;
this.r = result;
}
}
Should I keep the package _Mathematics.Problems.bin;, or should I change it to package _Mathematics.Problems.src;?
What is wrong with my code??
Help would be much appreciated.

Two issues worth mentioning:
bin directories are normally used for executable files. This is because (generally) your OS will have an environment setting that points to these directories, so when you try to run a program, it knows where to look. When you run a Java program, Java itself is the executable (your OS needs to know where to find it). The OS doesn't need to find your actual Java class files, Java needs to find them, for which it uses a completely different environment setting (the classpath). Because of this, if you're putting Java class files in a bin directory, you're probably doing something wrong.
Secondly, your package structure (_Mathematics.Problems.bin) should match exactly the directory structure, but it should reflect the purpose of the classes, so _Mathematics and Problems are reasonable parts of a package structure, but, again, bin or src, is not. Normally, I would create classes and src directories and then my package structure begins under there
So, as explained above, to fix the issue:
make sure the directory and package structures are identical for
your src and classes
by removing the bin part of your package structure, this will be
easier.

For class files, you need to maintain the folder structure which your program is expecting
_Mathematics\Problems\bin\Permutations

Exception in thread "main" java.lang.NoClassDefFoundError: =

I created a new maven project in Eclipse and on runtime I get this error:
Exception in thread "main" java.lang.NoClassDefFoundError: =
Caused by: java.lang.ClassNotFoundException: =
at java.net.URLClassLoader$1.run(URLClassLoader.java:217)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:205)
at java.lang.ClassLoader.loadClass(ClassLoader.java:321)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:294)
at java.lang.ClassLoader.loadClass(ClassLoader.java:266)
Could not find the main class: =. Program will exit.
In other threads the class is mentioned where the problem occurs but here it simply says nothing.
The code is also used in a different project (with slight tweaks in terms of calling a method) but the rest of it is same.
If anyone can help me resolve this issue..it will be highly appreciated.

It looks like something is passing in = as the class name. It doesn't say nothing - it says =.
For example, when I run:
java =
I get:
Error: Could not find or load main class =
There's no colon, but it's otherwise the same.
Look at where you're trying to specify the class name, and see whether there's a stray = around. For example, suppose you had:
java -Dfoo = bar ClassName
instead of
java -Dfoo=bar ClassName
You'd see the same thing. I'm not familiar with Maven, but if you ever specify a set of arguments in it, I'd look at that part of the configuration file.

Deleting the workspace worked for me.