In Java, what are keywords or reserved words used for?

Keywords or reserved words in Java serve specific roles defined by the language syntax. They are integral to the structure and functionality of Java code, as they convey instructions to the Java compiler on how to interpret and execute the code.

When the answer indicates that keywords are used to define specific compiler instructions, it highlights that these words have predefined meanings in the Java programming language. For instance, keywords like class, public, static, and void dictate how the code is compiled and executed. Their reserved nature means they cannot be used for any purpose other than their designated function.

Understanding keywords is essential for anyone programming in Java because they effectively form the building blocks of Java syntax. By knowing these reserved words, programmers can write code that the compiler can understand and process correctly.

In contrast, user-defined functions involve methods created by the programmer and are not part of the reserved keywords. Enhancing program readability may be a benefit of using keywords, but that is not their primary purpose. Similarly, creating custom variable types refers to class or data type creation, which also does not involve keywords directly.