Creating a program that works as javap tool
Following methods of java.lang.Class class can be used to display the metadata of a class.
Method Description
public Field[] getDeclaredFields() throws SecurityException returns an array of Field objects reflecting all the fields declared by the class or interface represented by this Class object.
public Constructor[] getDeclaredConstructors() throws SecurityException returns an array of Constructor objects reflecting all the constructors declared by the class represented by this Class object.
public Method[] getDeclaredMethods() throws SecurityException returns an array of Method objects reflecting all the methods declared by the class or interface represented by this Class object.
Example of creating javap tool
Let's create a program that works like javap tool.
public class MyJavap{
public static void main(String[] args)throws Exception {
Class c=Class.forName(args[0]);
System.out.println("Fields........");
Field f[]=c.getDeclaredFields();
for(int i=0;i<f.length;i++)
System.out.println(f[i]);
System.out.println("Constructors........");
Constructor con[]=c.getDeclaredConstructors();
for(int i=0;i<con.length;i++)
System.out.println(con[i]);
System.out.println("Methods........");
Method m[]=c.getDeclaredMethods();
for(int i=0;i<m.length;i++)
System.out.println(m[i]);
}
}
At runtime, you can get the details of any class, it may be user-defined or pre-defined class.
Output:
creating a program that works like javap tool creating a program that works like javap tool
