(import )public Method getMethods( ) Returns an array of all public methods in the current class, as well as those in all superclasses and superinterfaces.Ĭode Examples ReflectMethod.java & ReflectMethod2.java Class, Parent Class, Package nameShow all methods name, signatures – use getMethods()Bypassing Abstraction SpecificMethodInfoDemo.javaShowing method directly using getMethod()Bridge method ConceptSampleInvoke. (import )public Method getDeclaredMethods( ) Returns an array of all public and private methods declared in the current class or interface. Each wrapper class contains a field named TYPE which is equal to the Class for the primitive type being wrapped.Class c = Double.TYPE ġ8Class Methods(1 of 4)public String getName( ) Returns the name of the class referred to by the Class object.public booleanisInterface( ) Returns true if the Class object refers to an interface.public booleanisArray( ) Returns true if the Class object refers to an array type.public Class getSuperclass( ) Returns the superclass of the current Class object.ġ9Class Methods (2 of 4)public Class getInterfaces( ) Returns array of interface classes implemented by this class.public Class getClasses( ) Returns array of inner classes within this class.public Object newInstance( ) Creates and returns an instance of this class.public static Class forName( String name ) Returns a Class object corresponding to a class name (static method)Ģ0Class Methods (3 of 4)public Constructor getConstructors( ) Returns an array of all public constructors in the current class. class syntax, more convenient and the preferred way Class c = boolean.class Class c1 = String.class Class c2 = Employee.class All primitive types & void has a wrapper class in java.lang, used for boxing of primitive types to reference types. Retrieving Class Objects - ExamplesClass.forName()If the fully-qualified name of a class is available, it is possible to get the corresponding Class using the static method Class.forName()Class driverObject = Class.forName(“") Class c = Class.forName("")TYPE Field for Primitive Type WrappersTwo ways. boolean b Class c = b.getClass() // compile-time error Class c = boolean.class // correct Class c = java.io.PrintStream.class Class c = int.class class SyntaxIf the type is available but there is no instance then it is possible to obtain a Class by appending ".class" to the name of the type.This is also the easiest way to obtain the Class for a primitive type.
The returned Class corresponds to an array with component type byte. How objects workEvery object is either a reference or primitive type.objectclass Point Class c = A.getClass() A is is an instance of the enum E thus getClass() returns the Class corresponding to the enumeration type E.byte bytes = new byte Class c = bytes.getClass() Since arrays are Objects, it is also possible to invoke getClass() on an instance of an array.
Java reflection tutorial for beginners code#
Reflection OverviewReflection APIThe “Class" classClass methodsArray classMember interfaceMethod classinvoking a method, throwing exceptionsField classaccessible objectsīackgroundPrograms are just another kind of dataSource code is textManipulate it line by line, or by parsing expressionsCompiled programs are data, tooIntegers and strings are bytes in memory that you interpret a certain wayInstructions in methods are just bytes tooNo reason why a program can't inspect itself
Advanced Java ProgrammingLecture-02: ReflectionAatif Kamal, Dept.
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