Java Blocks

In Java, a block is a group of statements that are enclosed in curly braces {}. Blocks can be used to group statements together, to specify the body of a control statement (such as an if or for statement), or to define a local scope for variables.

Here are some examples of blocks in Java:

{
    // block of statements
    int x = 1;
    int y = 2;
    System.out.println(x + y);
}

if (x > 0) {
    // block of statements
    System.out.println("x is positive");
}

for (int i = 0; i < 10; i++) {
    // block of statements
    System.out.println(i);
}

In the first example, the block of statements is a standalone block that does not belong to any control statement. It defines a local scope for the variables x and y.

In the second and third examples, the blocks of statements are the bodies of the if and for statements, respectively. They are executed only if the condition of the if statement is true or the loop condition of the for statement is satisfied.

Blocks can also be nested inside other blocks. For example:

{
    // outer block
    int x = 1;
    {
        // inner block
        int y = 2;
        System.out.println(x + y);
    }
}

In this example, the inner block is nested inside the outer block. The inner block has access to the variables defined in the outer block, but the outer block does not have access to the variables defined in the inner block.

Note that a block cannot contain a label or be used as a statement. It can only contain declarations and statements.