Java Reflection API

Reflection API of java is a way to access and modify the state of any object includes constructors, fields, methods during the runtime.

It can access the metadata of a class and its members, including their types, modifiers, annotations, and generic information.

Methods

• getDeclaredFields() - return the list of fields of an object
• getDeclaredField(name) - return the particular field of an object
• get(object) - return the value of particular field of an object
• set(object, value) - assign the new value to the particular field of an object
• getDeclaredConstructors() - return the list of constructors of an object
• getDeclaredMethods() - return the list of methods of an object
• getDeclaredMethod(name) - return the particular field of an object
• setAccessible(true) - used to set the accessibility of a field or method
• invoke(object) - used to call the methods of an object

Limitations & risks

The Reflection API is powerful but also has below limitations and risks.

• Reflection API can be slower because it will do operations in runtime.
• Accessing or invoking private fields may violate encapsulation and security policies.
• Reflection API may not work correctly in dynamic code generation or bytecode manipulation operations.