What tools is used to test the java program?

Answer 1

These are the basics, so I guess by "test" you mean "verify that my source code compiles" (structure is right, all dependencies are meet, no typos). Therefore you need "javac" command. In some IDEs/editors it is called "Build the project" and shows you errors and warnings afterwards.

Please be aware, that the term "testing" in software development in general means "verify that my code does the things I wrote it for", which needs your code to compile first. This involves other tools/libraries/frameworks that are not part of Java itself.

Answer 2

You should be having IDE ( Integrated Development Kit) like Eclipse which understand your '.java' code. That compiles the Java code and make it run in it. Then you can see the error if it has any.