Few Tricky Programs in Java

Comments that execute : Till now, we were always taught "Comments do not Execute". Let us see today "The comments that execute" Following is the code snippet:

Java

public class Testing {
    public static void main(String[] args)
     {
         // the line below this gives an output
         // \u000d System.out.println("comment executed");
     }
}

Output:

comment executed

The reason for this is that the Java compiler parses the unicode character \u000d as a new line and gets transformed into:

Java

public class Testing {
    public static void main(String[] args)
    {
        // the line below this gives an output
        // \u000d
        System.out.println("comment executed");
    }
}

Named loops :

Java

// A Java program to demonstrate working of named loops.
public class Testing 
{
    public static void main(String[] args)
    {
    loop1:
    for (int i = 0; i < 5; i++)
     {
        for (int j = 0; j < 5; j++) 
        {
            if (i == 3)
                break loop1;
            System.out.println("i = " + i + " j = " + j);
        }
    }
   }
}

Output:

i = 0 j = 0
i = 0 j = 1
i = 0 j = 2
i = 0 j = 3
i = 0 j = 4
i = 1 j = 0
i = 1 j = 1
i = 1 j = 2
i = 1 j = 3
i = 1 j = 4
i = 2 j = 0
i = 2 j = 1
i = 2 j = 2
i = 2 j = 3
i = 2 j = 4

You can also use continue to jump to start of the named loop. We can also use break (or continue) in a nested if-else with for loops in order to break several loops with if-else, so one can avoid setting lot of flags and testing them in the if-else in order to continue or not in this nested level.

Few Tricky Programs in Java

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