Can we execute a program without main() method?

Naveen Arumugam

9y3kJava

In Java we can execute the program without main method can we give some examples??

7 Replies

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Mukil Vendhan9y ago
Yes, sequence is as follows:
- jvm loads class
- executes static blocks
- looks for main method and invokes it
So, if there's code in a static block, it will be executed. But there's no point in doing that.
How to test that:
```
public final class Test { static { System.out.println("FOO"); } }
```
Then if you try to run the class (either form command line with java Test or with an IDE), the result is:
0
Rajkiran Swain9y ago
Yes their is a way to run a JAVA program without the main method.
Code for That
public class Manish{
static{
System.out.println("Hello World");
System.exit(0);
}
Now you can compile the program using javac Manish.java
and after that run it using java Manish.
It will print the message as expected. But it will show a message
"Exception in thread "main" java.lang.NoSuchMethodError: main"
To avoid this message I have added System.exit(0); after print statement The System.exit(0) lets the program exit before the JVM is looking for the main method.
One more thing this Up to and including Java 6 it was possible to do this using the Static Initialization block but In Java 7, however, this does not work anymore, even though it compiles, the following error will appear when you try to execute it:
"The program compiled successfully, but main class was not found. Main class should contain method: public static void main (String[] args)."
I hope it makes the thing clear.:)
0
Manikandan Murugesan9y ago
Yes , You can compile and execute without main method. By using static block. But after static block executed (printed) you will get an error saying no main method found. And Latest INFO --> YOU cant Do this with JAVA 7 version. IT will not execute
{
    static
    {
        System.out.println("Hello World!");
        System.exit(0); // prevents “main method not found” error
    }
}
Or
Refer the following Link : https://stackoverflow.com/questions/11421542/how-can-you-run-a-java-program-without-main-method
0
Guest User9y ago
The main method is only used when the Java Virtual Machine is executing your code. Code cannot be executed without a main method but it can still be compiled. When compiling code, you usually specify a set of files on the command line e.g. javac MyClass1.java MyClass2.java The Java compiler (javac) examines each class you passed to it and compiles it into a .class file. One reason Java source code may be missing a main method is because it is designed to be used as a library, instead of being executed. Something you may find interesting: although the source code compiled by the Java compiler does not need a mainmethod, the source code for the Java compiler itself does have a main method
0
Vivek Kumar9y ago
Hi Naveen,

Please find below link for detail explaination.

http://www.java67.com/2014/02/can-you-run-java-program-without-main-method.html
0
Naveen Arumugam9y ago
Its simple can we explain more....
0
Mobeen Rashid9y ago
you can do that by creating a static code block like this
public final class Test {
    static {
        System.out.println("FOO");
    }
}
JVM will execute that code block before searching for main method but there is no point in doing that, how will you test it?
0