Annotations in Java are a form of syntactic metadata that provide additional information about the program without affecting its execution. They can be applied to various program constructs, such as classes, methods, and variables, to convey specific instructions or information to the compiler and other tools. Annotations serve multiple purposes, including error detection, code generation, and enhancing code readability. They are defined using the “@” symbol followed by the annotation name, and can include parameters. Java provides several predefined annotations, and developers can also create custom annotations to suit their specific needs ¹²³⁴.