Java数组，除了重复值、增加、删除数组元素

Java数组，去掉重复值、增加、删除数组元素
import java.util.List; 
import java.util.ArrayList; 
import java.util.Set; 
import java.util.HashSet; 
public class lzwCode { 
 
    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]); 
            } 
        } 
        /*
        Set<String> set = new HashSet<String>();
        for (int i=0; i<str.length; i++) {
            set.add(str[i]);
        }
        String[] newStr =  set.toArray(new String[1]); 
        */ 
        System.out.println(); 
        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"}; 
        for (String elementA:str ) { 
            System.out.print(elementA + " "); 
        } 
        //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")  
        System.out.println(); 
        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(); 
    } 
 
    //在数组中增加一个元素 
    public static void testC() { 
        String [] str = {"Java", "C++", "Php", "C#", "Python"}; 
        for (String elementA:str ) { 
            System.out.print(elementA + " "); 
        } 
        //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"); //list.add("ruby")  
        System.out.println(); 
        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(); 
    } 
}