从命令行运行Java代码

Question

I'm on Mac OS X 10.9.2 (Mavericks). I have code that uses an external Java library (twitter4j). It runs fine when I run it through NetBeans. However, trying to run almost identical code in the terminal gives me errors.

My directory structure is straightforward- I have a 'src' folder with the .java file and a 'lib' folder with the external .jar files I use.

From the src folder, I call javac -cp "../lib/*" MyProgram.java which seems to work alright. Now, if I call java MyProgram , I get an exception:

Exception in thread "main" java.lang.NoClassDefFoundError: twitter4j/StreamListener
at java.lang.Class.getDeclaredMethods0(Native Method)
at java.lang.Class.privateGetDeclaredMethods(Class.java:2693)
at java.lang.Class.privateGetMethodRecursive(Class.java:3040)
at java.lang.Class.getMethod0(Class.java:3010)
at java.lang.Class.getMethod(Class.java:1776)
at sun.launcher.LauncherHelper.validateMainClass(LauncherHelper.java:544)
at sun.launcher.LauncherHelper.checkAndLoadMain(LauncherHelper.java:526)
Caused by: java.lang.ClassNotFoundException: twitter4j.StreamListener
at java.net.URLClassLoader$1.run(URLClassLoader.java:372)
at java.net.URLClassLoader$1.run(URLClassLoader.java:361)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:360)
at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)

It seems to have trouble properly importing the external twitter4j library. What am I missing here?

These are my import statements in the code: import twitter4j.*; , import twitter4j.conf.ConfigurationBuilder;

UPDATE: Using suggestions below, I also tried running it via java -cp "../lib/*" MyProgram which gives: "Could not find or load main class MyProgram"

Answer 1

You need to specify the classpath when running the program as well as when compiling it:

Eg

java -cp "../lib/*" MyProgram