[java] Running Java Program from Command Line Linux

I am not very experience with java and this is driving me crazy. I wrote a java program FileManagement and I need to run it from the command line.

I can compile it from the command line with javac FileManagement/*.java which will create all the classes in that folder but when I try java FileManagement.Main it says :

Exception in thread "main" java.lang.NoClassDefFoundError: FileManagement/Main

The thing is that I have tried this same procedure in a remote computer and it is working fine. It is not working on mine.

(This is the KISS answer.)

Let's say you have several .java files in the current directory:

$ ls -1 *.java
javaFileName1.java
javaFileName2.java

Let's say each of them have a main() method (so they are programs, not libs), then to compile them do:

javac *.java -d .

This will generate as many subfolders as "packages" the .java files are associated to. In my case all java files where inside under the same package name packageName, so only one folder was generated with that name, so to execute each of them:

java -cp . packageName.javaFileName1
java -cp . packageName.javaFileName2

What is the package name of your class? If there is no package name, then most likely the solution is:

java -cp FileManagement Main

Guys let's understand the syntax of it.

1. If class file is present in the Current Dir.

   java -cp . fileName

2. If class file is present within the Dir. Go to the Parent Dir and enter below cmd.

   java -cp . dir1.dir2.dir3.fileName

3. If there is a dependency on external jars then,

   java -cp .:./jarName1:./jarName2 fileName

   Hope this helps.