private static void method1Test() { //新建一个实现类对象 GenericInterfaceImpl gc1=new GenericInterfaceImpl(); gc1.method1("ABC"+100); } private static void method2Test() { //新建一个实现类对象 String类型 GenericInterfaceImpl2<String> gc2=new GenericInterfaceImpl2<>(); gc2.method1("ABC"...
WildcardError.java:6: error: method set in interface List<E> cannot be applied to given types; i.set(0, i.get(0)); ^ required: int,CAP#1 found: int,Object reason: actual argument Object cannot be converted to CAP#1 by method invocation conversion where E is a type-variable: E exte...
System.out.println("---接口实现 String---"); InterfaceImpl impl=newInterfaceImpl(); impl.server("hello"); InterfaceImpl2<Integer> impl2=newInterfaceImpl2<>(); impl2.server(100); GenericMethod genericMethod=newGenericMethod(); genericMethod.show("Hello"); genericMethod.show(100); } }...
public interface Collection<E>{ boolean <T> containAll(Collection<T> c);boolean<T extends E> addAll(Collection<T> c); ... } 上面方法使用了 <T extends E> 泛型形式,这时定义类型形参时设定上限(其中 E 是 Collection 接口里定义的类型形参,在该接口里E可当成普通类型使用)。 上面两个方法中类型...
publlc interface Iterator<E>{ E next(); } 1. 2. 3. 第一种方式: 创建接口 public interface GenericInterface<I> { public abstract void method(I i); } 1. 2. 3. 实现类 public class GenericInterfaceImpl implements GenericInterface<String>{ ...
public class GenericInterfaceImpl01 implements GenericInterface<String> {public void method(String s){ System.out.println(s); }} 含有泛型的接口第二种使用方式:接口使用什么泛型,实现类就使用什么泛型,类跟着接口走,就相当于,定义了一个含有泛型的类,创建对象的时候确定泛型的类型。public interface List<E>...
If thisClassobject represents a class or interface that implements no interfaces, the method returns an array of length 0. If thisClassobject represents a primitive type or void, the method returns an array of length 0. If thisClassobject represents an array type, the interfacesCloneableandjava...
We could have used generic methods here instead:interface Collection<E> { public <T> boolean containsAll(Collection<T> c); public <T extends E> boolean addAll(Collection<T> c); // Hey, type variables can have bounds too! } However, in both containsAll and addAll, the type parameter T...
Erasure forgets the base-class type, so a generic class cannot inherit directly from a generic parameter. 第一种方式:通过接口 // : generics/Mixins.java import java.util.Date; interface TimeStamped { long getStamp(); } class TimeStampedImp implements TimeStamped { private final long timeSta...
is straightforward, but it does not compile because the greater than operator (>) applies only to primitive types such asshort,int,double,long,float,byte, andchar. You cannot use the>operator to compare objects. To fix the problem, use a type parameter bounded by theComparable<T>interface:...