In Java, expressions are evaluated within the context of statements, which are fundamental units of code that dictate the actions a program performs. These statements are used for a variety of tasks, such as declaring variables, making decisions, and controlling the flow of execution. Java supports two types of statements: simple and compound. Each serves a unique purpose and plays an essential role in writing clear and efficient code.
A simple statement is essentially a single, standalone instruction that performs a specific task. It is typically terminated with a semicolon (;), which signals the end of the instruction. For example, assigning a value to a variable or calling a method can be considered simple statements. These are straightforward and are the building blocks for more complex actions in Java programs.
On the other hand, a compound statement consists of a group of simple and possibly other compound statements enclosed within curly braces ({…}). This structure allows you to group multiple statements together and treat them as a single unit. Compound statements, often referred to as blocks, do not require a semicolon at the end. They provide a way to organize and control the flow of execution, especially when conditions or loops are involved, making your code more structured and readable.
In Java, there are various statements used for control flow, such as if, if-else, switch, for, and while. These allow you to declare variables, make decisions, and repeat actions (iteration). For example, conditional statements help in making decisions based on certain conditions, while looping statements allow for repetition until a specific condition is met. These statements can also be used with keywords like break and continue to control the flow within loops. Additionally, understanding how to declare variables and assign values to them is crucial in any Java program, as they form the foundation for most operations. A variable declaration is a statement in itself, where the type of the variable is specified, and it may optionally be initialized with a value.