Java Tutorial/Reflection/Name

Get full class name

   <source lang="java">

public class Main {

 public static String getFullClassName(Class c) {
   return c.getName();
 }

 public static void main(String[] args) {
   System.out.println(getFullClassName(java.awt.Frame.class));
 }

}</source>

Get the class name in a static method

   <source lang="java">

public class Main{

 public static void main(java.lang.String[] args) {
   System.out.println("in " + new CurrentClassGetter().getClassName() + " class");
 }

}

class CurrentClassGetter extends SecurityManager {
 public String getClassName() {
   return getClassContext()[1].getName();
 }

}</source>

Get the fully-qualified name of a class

   <source lang="java">

public class Main {

 public static void main(String[] argv) throws Exception {
   Class cls = java.lang.String.class;
   String name = cls.getName(); 
   System.out.println(name);
 }

}</source>

Get the fully-qualified name of a inner class

   <source lang="java">

public class Main {

 public static void main(String[] argv) throws Exception {
   Class cls = java.util.Map.Entry.class;
   String name = cls.getName(); 
   System.out.println(name);
 }

}</source>

Get the name of a class

   <source lang="java">

import java.util.Calendar; import java.math.BigDecimal; public class Main {

 public static void main(String[] args) {
   // Get the name of the classes below.
   Class clazz = String.class;
   System.out.println("Class Name: " + clazz.getName());
   clazz = Calendar.class;
   System.out.println("Class Name: " + clazz.getName());
   clazz = BigDecimal.class;
   System.out.println("Class Name: " + clazz.getName());
 }

}</source>

Get the name of an array

   <source lang="java">

public class Main {

 public static void main(String[] argv) throws Exception {
   String name = boolean[].class.getName();
   System.out.println(name);
   name = byte[].class.getName();
   System.out.println(name);
   name = char[].class.getName();
   System.out.println(name);
   name = short[].class.getName();
   System.out.println(name);
   name = int[].class.getName();
   System.out.println(name);
   name = long[].class.getName();
   System.out.println(name);
   name = float[].class.getName();
   System.out.println(name);
   name = double[].class.getName();
   System.out.println(name);
   name = String[].class.getName();
   System.out.println(name);
   name = int[][].class.getName();
   System.out.println(name);
 }

}</source>

Get the name of void

   <source lang="java">

public class Main {

 public static void main(String[] argv) throws Exception {
   Class cls = Void.TYPE;
   String name = cls.getName(); // void
 }

}</source>

Get the unqualified name of a class

   <source lang="java">

public class Main {

 public static void main(String[] argv) throws Exception {
   Class cls = java.util.Map.Entry.class;
   String name = cls.getName();
   if (name.lastIndexOf(".") > 0) {
     name = name.substring(name.lastIndexOf(".") + 1); // Map$Entry
     name = name.replace("$", ".");      // Map.Entry
   }
 }

}</source>

Getting the Name of a Member Object

   <source lang="java">

import java.lang.reflect.Constructor; import java.lang.reflect.Field; import java.lang.reflect.Method; public class Main {

 public static void main(String[] argv) throws Exception {
   Class cls = java.lang.String.class;
   Method method = cls.getMethods()[0];
   Field field = cls.getFields()[0];
   Constructor constructor = cls.getConstructors()[0];
   String name;
   name = cls.getName();
   System.out.println(name);
   name = cls.getName() + "." + field.getName();
   System.out.println(name);
   name = constructor.getName();
   System.out.println(name);
   name = cls.getName() + "." + method.getName();
   System.out.println(name);
 }

} /* java.lang.String java.lang.String.CASE_INSENSITIVE_ORDER java.lang.String java.lang.String.hashCode

• /</source>

Unqualified names

   <source lang="java">

import java.lang.reflect.Constructor; import java.lang.reflect.Field; import java.lang.reflect.Method; public class Main {

 public static void main(String[] argv) throws Exception {
   Class cls = java.lang.String.class;
   Method method = cls.getMethods()[0];
   Field field = cls.getFields()[0];
   Constructor constructor = cls.getConstructors()[0];
   String name;
   name = cls.getName().substring(cls.getPackage().getName().length()+1);  
   System.out.println(name);
   name = field.getName();  
   System.out.println(name);
   name = constructor.getName().substring(cls.getPackage().getName().length()+1);
   System.out.println(name);
   name = method.getName(); 
   System.out.println(name);
 }

} /*String CASE_INSENSITIVE_ORDER String hashCode

• /</source>

Use Class.forName to load a class

   <source lang="java">

import java.lang.reflect.Constructor; import java.lang.reflect.Field; import java.lang.reflect.Method; public class Main{

 public static void main(String args[]) throws Exception {
   Class c = Class.forName("MyClass");
 }

} class MyClass {

 private int count;
 MyClass(int c) {
   count = c;
 }
 MyClass() {
   count = 0;
 }
 void setCount(int c) {
   count = c;
 }
 int getCount() {
   return count;
 }
 void showcount() {
   System.out.println("count is " + count);
 }

}</source>