Info Tech Guide

Now  it's time to learn about expressions, statements, and blocks in Java. Operators may be used in building expressions, which compute values; expressions are the core components of statements; statements may be grouped into blocks.

An expression is a construct made up of variables, operators, and method invocations, which are constructed according to the syntax of the language, that evaluates to a single value. 

Examples of expressions, illustrated in bold below:

int cadence = 0;

anArray[0] = 100;

System.out.println("Element 1 at index 0: " + anArray[0]);

int result = 1 + 2; // result is now 3

if(value1 == value2) System.out.println("value1 == value2");

aValue = 8933.234; // assignment statement

aValue++; // increment statement

System.out.println("Hello World!"); // method invocation statement

Bicycle myBike = new Bicycle(); // object creation statement

A block is a group of zero or more statements between balanced braces and can be used anywhere a single statement is allowed. 

The following example, BlockDemo, illustrates the use of blocks:

class BlockDemo {

public static void main(String[] args) {

boolean condition = true;

if (condition) { // begin block 1

System.out.println("Condition is true.");

} // end block one

else { // begin block 2

System.out.println("Condition is false.");

} // end block 2

}

}