javac : Compiling a .java file which uses other classes in it

Question

HI i have 3 java files

a.java  
b.java  
c.java  

I managed to generate .class files for both a and b using

javac example/a         


        

Answer 1

You have to have classes a and b in your classpath when you try to compile class c. This allows the compiler to verify that they exist, figure out what methods they have, etc.

javac is pretty sensitive to package names and classpaths. The easiest thing to do is to compile all three at the same time like so javac example/a.java example/b.java example/c.java.

If you go to the parent directory of example (let's call it src), then you can run the following:

javac -cp src src/example/c.java

The reason you have to do it this way is because your classes have their packages listed as example. Because of your package name, javac is looking for the example directory in its classpath, where it expects to find a.class and b.class.

Answer 2

Presumably you're not in the example/ directory when you run javac. Try

javac -cp example c.java

Or just cd into that directory. The classpath is not automatically resolved for the classes c.java depends on.