Java 8中的IncompatibleClassChangeError（Lambda表达式）

Question

我正在尝试学习lambda表达式，所以请关注http://www.oracle.com/technetwork/articles/java/lambda-1984522.html 。 下载了IDE和JDK

支持JDK 8的JDK 8 Eclipse IDE

但是在编译下面的代码后，我有一个例外

Exception in thread "main" java.lang.IncompatibleClassChangeError
    at java.lang.invoke.MethodHandleNatives.linkMethodHandleConstant(MethodHandleNatives.java:444)
    at com.ahmetk.java8.Hello.main(Hello.java:10)
Caused by: java.lang.NoSuchMethodException: no such method: java.lang.invoke.LambdaMetafactory.metaFactory(Lookup,String,MethodType,MethodHandle,MethodHandle,MethodType)CallSite/invokeStatic
    at java.lang.invoke.MemberName.makeAccessException(MemberName.java:800)
    at java.lang.invoke.MemberName$Factory.resolveOrFail(MemberName.java:917)
    at java.lang.invoke.MethodHandles$Lookup.resolveOrFail(MethodHandles.java:1101)
    at java.lang.invoke.MethodHandles$Lookup.linkMethodHandleConstant(MethodHandles.java:1363)
    at java.lang.invoke.MethodHandleNatives.linkMethodHandleConstant(MethodHandleNatives.java:442)
    ... 1 more
Caused by: java.lang.NoSuchMethodError: java.lang.invoke.LambdaMetafactory.metaFactory(Ljava/lang/invoke/MethodHandles$Lookup;Ljava/lang/String;Ljava/lang/invoke/MethodType;Ljava/lang/invoke/MethodHandle;Ljava/lang/invoke/MethodHandle;Ljava/lang/invoke/MethodType;)Ljava/lang/invoke/CallSite;
    at java.lang.invoke.MethodHandleNatives.resolve(Native Method)
    at java.lang.invoke.MemberName$Factory.resolve(MemberName.java:889)
    at java.lang.invoke.MemberName$Factory.resolveOrFail(MemberName.java:914)

我想要执行的简单代码。

public class Hello {
    interface HelloService {
        String hello(String firstname, String lastname);
    }

    public static void main(String[] args) {

        HelloService helloService = (String firstname, String lastname) -> {
            String hello = "Hello " + firstname + " " + lastname;
            return hello;
        };
        System.out.println(helloService.hello(args[0], args[1]));

    }
}

Answer 1

eclipse在支持java8方面存在问题。 我已成功编译并在命令提示符下运行

D：\\ tools \\ java \\ jdk1.8.0_32Bit \\ bin \\ javac com / ahmetk / java8 / Hello.java

D：\\ tools \\ java \\ jdk1.8.0_32Bit \\ bin \\ java -cp。 com.ahmetk.java8.Hello 12 12你好12 12

Answer 2

如果您正在使用Maven，请在您的pom.xml中添加

  <build>  
    <plugins>
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-compiler-plugin</artifactId>
            <version>2.3.2</version>
            <configuration>
                <source>1.8</source>
                <target>1.8</target>
            </configuration>
        </plugin>
    </plugins>
  </build>