When we write a Java program, the code needs to be processed by a compiler before it can be executed. The compilation process in Java is a crucial step in turning our human-readable code into a machine-readable format. It involves several stages that ensure the code is syntactically correct, resolves any references to other classes or libraries, and ultimately generates byte code that can be executed by the Java Virtual Machine (JVM).

The first step in the compilation process is known as lexical analysis or tokenization. The compiler reads the source code character by character and builds tokens based on predefined patterns. These tokens include keywords, identifiers, operators, and literals. This step helps the compiler recognize the different elements in the code and their meanings. For example, it can distinguish between a variable declaration and an arithmetic operation by recognizing different keywords and operators.

Once the tokens have been identified, the compiler moves on to the syntax analysis or parsing phase. During this stage, the compiler applies a set of grammar rules to determine the structure and correctness of the code. It checks if the tokens are arranged properly according to the language's syntax rules. For instance, it verifies that opening and closing parentheses match, that semicolons are used to terminate statements, and that conditional statements have proper if-else structures. If the code violates any of these rules, the compiler will report an error and provide a meaningful message to help us identify and fix the issue.