public class ThisDemo {String name="Nick";public void print(String name){System.out.println("这个类中的名字： "+this.name);System.out.println("局部变量中的名字： "+name);}public static void main(String[] args){ThisDemo td=new ThisDemo();td.print("cena");}
}

这个类中的名字： Nick
局部变量中的名字： cena

public class NameAndAge {private String name;private int age;public NameAndAge(){this.age=24;}public NameAndAge(String name,int age){this();this.name=name;}public void print(){System.out.println("最终的姓名：" +name);System.out.println("最终的年龄： "+age);}public static void main(String[] args){NameAndAge naa=new NameAndAge("cena",20);naa.print();}
}

最终的姓名：cena
最终的年龄： 24

public class AddingGroups {public static void main(String[] args){Collection<Integer> collection=new ArrayList<Integer>(Arrays.asList(1,2,3,4,5));//将元素列表(1,2,3,4,5)转化为List添加到collection中Integer[] moreInts={6,7,8,9,10};collection.addAll(Arrays.asList(moreInts));//将数组转化为list添加到collection中，而Collections.AddAll()方法接受一个Colletion对象，以及一个                                                    数组或是一个用逗号分隔的列表，将元素添加到Collection中//collection.addAll(collection,11,12,13,14,15);//collection.addAll(collection,moreInts);List<Integer> list=Arrays.asList(16,17,18,19,20);list.set(1, 99);//将第一个位置的数设为99System.out.println(collection);System.out.println(list);}
}

[1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
[16, 99, 18, 19, 20]

public class PrintingContainers {static Collection fill(Collection<String> collection){collection.add("rat");collection.add("cat");collection.add("dog");collection.add("dog");return collection;}static Map fill(Map<String,String> map){map.put("rat", "Fuzzy");map.put("cat", "Rags");map.put("dog", "Bosco");map.put("dog", "Spot");return map;}public static void main(String[] args){System.out.println(fill(new ArrayList<String>()));System.out.println(fill(new LinkedList<String>()));System.out.println(fill(new HashSet<String>()));System.out.println(fill(new TreeSet<String>()));System.out.println(fill(new LinkedHashSet<String>()));System.out.println(fill(new HashMap<String,String>()));System.out.println(fill(new TreeMap<String,String>()));System.out.println(fill(new LinkedHashMap<String,String>()));}
}

[rat, cat, dog, dog]
[rat, cat, dog, dog]
[dog, cat, rat]
[cat, dog, rat]
[rat, cat, dog]
{dog=Spot, cat=Rags, rat=Fuzzy}
{cat=Rags, dog=Spot, rat=Fuzzy}
{rat=Fuzzy, cat=Rags, dog=Spot}