Why am I getting a NoClassDefFoundError when I run a Java class file from the command line in Linux?

Question

I am trying to run a test.class file from the linux command line. I compiled the file using javac test.java which produced the test.class file. When I run the command java test it throws a class not found exception. I also tried specifying the package name with the same result. Here is the output, can anybody help? I believe my syntax is correct according to Google searches.

[root@localhost usr]# java test
Exception in thread "main" java.lang.NoClassDefFoundError: test (wrong name: testJava/test)
        at java.lang.ClassLoader.defineClass1(Native Method)
        at java.lang.ClassLoader.defineClass(ClassLoader.java:634)
        at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
        at java.net.URLClassLoader.defineClass(URLClassLoader.java:277)
        at java.net.URLClassLoader.access$000(URLClassLoader.java:73)
        at java.net.URLClassLoader$1.run(URLClassLoader.java:212)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.net.URLClassLoader.findClass(URLClassLoader.java:205)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:321)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:294)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:266)
Could not find the main class: test. Program will exit.

Answer 1

Use java testJava.test from the parent directory of testJava