JDK8 Parameter Names sample

ParamEx.java

/*
 * JDK 8 javac has a new option -parameters.
 * If this option was used, parameter name is stored in class file.
 * The parameter name can be obtained via reflection.  New class
 * Parameter and a new method Method#getParameters() was added.
 * $ ~/local/jdk1.8.0/bin/java ParamEx
 * method: main
 *   param: java.lang.String[] arg0
 * method: doit
 *   param: java.lang.String arg0
 *   param: int arg1
 * $ ~/local/jdk1.8.0/bin/javac -parameters ParamEx.java
 * $ ~/local/jdk1.8.0/bin/java ParamEx
 * method: main
 *   param: java.lang.String[] args
 * method: doit
 *   param: java.lang.String name
 *   param: int iarg1
 */

import java.lang.reflect.Method;
import java.lang.reflect.Parameter;

public class ParamEx {
  public static void main(String[] args) {
    showParamInfo(ParamEx.class, "main", String[].class);
    showParamInfo(ParamEx.class, "doit", String.class, int.class);
  }
  static void showParamInfo(Class<?> c, String mn, Class<?>... parameterTypes) {
    try {
      Method m = c.getMethod(mn, parameterTypes);
      P("method: " + mn);
      for (Parameter p : m.getParameters()) {
        P("  param: " + p);
      }
    } catch (Exception e) {
      e.printStackTrace();
    }
  }

  public void doit(String name, int iarg1) {
    System.out.println(name + "" + iarg1);
  }
  static void P(Object o) { System.out.println(o); }
  static void I(Object o) { System.out.println("I: " + o); }
  static void W(Object o) { System.out.println("I: " + o); }
  static void E(Object o) { System.out.println("I: " + o); }
}