import java.util.List;import java.util.ArrayList;import java.util.Set;import java.util.HashSet;public class Code {    public static void main(String [] args) {        testA();        System.out.println("===========================");        testB();        System.out.println("===========================");        testC();    }    //去掉数组中重复的值    public static void testA() {        String [] str = {"Java", "C++", "Php", "C#", "Python", "C++", "Java"};        for (String elementA:str ) {            System.out.print(elementA + " ");        }        List<String> list = new ArrayList<String>();        for (int i=0; i<str.length; i++) {            if(!list.contains(str[i])) {                list.add(str[i]);            }        }        String[] newStr =  list.toArray(new String[1]); //返回一个包含所有对象的指定类型的数组         for (String elementB:newStr ) {            System.out.print(elementB + " ");        }        System.out.println();    }    //删除数组中其中一个元素    public static void testB() {        String [] str = {"Java", "C++", "Php", "C#", "Python"};//删除php        List<String> list = new ArrayList<String>();        for (int i=0; i<str.length; i++) {            list.add(str[i]);        }        list.remove(2); //list.remove("Php")           String[] newStr =  list.toArray(new String[1]); //返回一个包含所有对象的指定类型的数组     }    //在数组中增加一个元素    public static void testC() {        String [] str = {"Java", "C++", "Php", "C#", "Python"};//增加ruby        List<String> list = new ArrayList<String>();        for (int i=0; i<str.length; i++) {            list.add(str[i]);        }        list.add(2, "ruby");         String[] newStr =  list.toArray(new String[1]); //返回一个包含所有对象的指定类型的数组     }}