Get the package name of the specified class. : Package « Reflection « Java Tutorial

1. Java Tutorial
2. Reflection
3. Package

import java.lang.reflect.Method;
import java.net.URL;
import java.security.CodeSource;
import java.security.ProtectionDomain;
import java.util.HashSet;
import java.util.List;
import java.util.Set;

/*
 * JBoss, Home of Professional Open Source
 * Copyright 2005, JBoss Inc., and individual contributors as indicated
 * by the @authors tag. See the copyright.txt in the distribution for a
 * full listing of individual contributors.
 *
 * This is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation; either version 2.1 of
 * the License, or (at your option) any later version.
 *
 * This software is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this software; if not, write to the Free
 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
 */

public class Main {

  /** The string used to separator packages */
  public static final String PACKAGE_SEPARATOR = ".";

  /**
   * Get the package name of the specified class.
   * 
   * @param classname
   *          Class name.
   * @return Package name or "" if the classname is in the <i>default</i>
   *         package.
   * 
   * @throws EmptyStringException
   *           Classname is an empty string.
   */
  public static String getPackageName(final String classname) {
    if (classname.length() == 0)
      System.out.println("Empty String Exception");

    int index = classname.lastIndexOf(PACKAGE_SEPARATOR);
    if (index != -1)
      return classname.substring(0, index);
    return "";
  }
}