Wednesday, 24 September 2014

Can We Running javaProgram without main()? is it possible in JDK1.7 latest Version

it is not possible in in JDK1.7...gone are the days now.

Running Java Program without main() has become an old story now.
So far we used to write the program like this
StaticDemo.java
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public class StaticDemo
{
   static
    {
        System.out.println("Hello");
        System.out.exit(0);
     }
}
And then >javac *.java>java StaticDemo
It compiles and runs successfully,printing Hello
This works well in JDK1.7 old versions(build 1.7.0-ea-b19)
But From jdk 1.7(build1.7.0-ea-b85),It gives run time Exception
Error: Main method not found in class StaticDemo, please define the main method
public static void main(String[] args)
The latest version while writing this article was build  jdk 1.7(build 1.7.0_03-b05),which also doesnot allow running java program without main();
So the Concept is:
When we say
java StaticDemo
Compiler understands that we are trying to execute the program,so before executing the static block,it first checks whether main() is there or not.If not,throws Exception

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