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Answer 1

+4 A:

The java program will not automatically include JAR files in its class path. You add a JAR file to its class path via the -classpath option. For example:

java -classpath .;yourJarFile.jar your.MainClass

Eclipse is automatically adding the JAR file whenever you run the program.

Note: The -classpath option expects a semicolon (;) when running on Windows and a colon (:) otherwise.

Adam Paynter 2009-07-20 12:25:06

I guess you are right. Now if the Jar File uses any other Jar File I should add that too?

Geek 2009-07-20 12:30:40

Unfortunately, yes. http://en.wikipedia.org/wiki/Dependency_hell

Adam Paynter 2009-07-20 12:31:38

http://en.wikipedia.org/wiki/JAR_hell#JAR_hell

Adam Paynter 2009-07-20 12:32:24

Thanks mate. Dude can you give me an example of two Jar Files. ? On a unix system.

Geek 2009-07-20 12:34:06

You just separate all the JAR file names with a colon (`:`) on a UNIX system:`java -classpath .:firstJarFile.jar:secondJarFile.jar your.MainClass

Adam Paynter 2009-07-20 12:41:32

Answer 2

+1 A:

JAR files are not automatically included in the classpath. You can add a Class-Path entry and a Main-Class entry to the to JAR file containing the main method that you wish to execute. Then you can execute your code like so:

java -jar yourJarFile.jar

See the JAR File Specification for more details.

or specify the classpath on the command line:

java -classpath lib1.jar:lib2.jar:yourJarFile.jar your.MainClass

NullPointerException 2009-07-20 22:04:34

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