Java main class instance access

Question

I am not able to compile the following code. Not able to understand the compilation process here. why the main class instances are not been visible to other classes(test1). why it failing at compilation. Please help.

public class test {
    public int i = 10;
    public static void main(String[] args) {
           System.out.println("test main");
    }
}
class test1 {
     test t = new test();
     System.out.println(t.i);
 }

How many files do you have? What is the exact content of each of them? — sp00m, Dec 20 '13 at 10:39
here is the error test.java:9: error: expected System.out.println(t.i); ^ test.java:9: error: expected System.out.println(t.i); ^ 2 errors — Akhil Srivastava, Dec 20 '13 at 10:39

score 7 · Answer 1 · edited May 23 '17 at 12:28

7

The System.out.println(t.i); statement should be within a block or method.

For example, you can either place it within a block (static or non-static, nevermind).

public class test1 {
    test t = new test();

    static { //static can be omitted
        System.out.println(t.i);
    }
}

Or place is within a method

public class test1 {
    test t = new test();

    public static void printSomething() { //static can be omitted
        System.out.println(t.i);
    }
}

More info (thanks to @vidudaya):

Why does System.out.println() have to be inside a method ?

edited May 23 '17 at 12:28

Community

1
1

answered Dec 20 '13 at 10:38

Konstantin Yovkov

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i want to know what is the problem with this. Will placing it in a static block work(compilation)? – Akhil Srivastava Dec 20 '13 at 10:42
Either place it within a block (static or non-static, nevermind) or within a method. – Konstantin Yovkov Dec 20 '13 at 10:42
2

check [this](http://stackoverflow.com/questions/15901973/why-does-system-out-println-have-to-be-inside-a-method) – prime Dec 20 '13 at 10:43
thanks kocko. what i want to understand is the rationale behind it. – Akhil Srivastava Dec 20 '13 at 10:47

Aniket Thakur · Answer 2 · 2013-12-20T10:43:29.260

System.out.println(t.i);

must be inside some method.

public class Test {
    public int i = 10;
    public static void main(String[] args) {
        System.out.println("test main");
    }
}


class Test1 {

    Test t = new Test();

    public void printI(){
        System.out.println(t.i);
    }

}

Also stick to java naming conventions. Class names must start with capital letters. variables and methods must be in camel case.

Java main class instance access

2 Answers2