maven-plugin-plugin:描述符目标在文件和文件中失败

在开发maven插件时,构建打印错误:

[ERROR] Failed to execute goal org.apache.maven.plugins:maven-plugin-plugin:3.3:descriptor (default-descriptor) on project default-method-demo: Execution default-descriptor of goal org.apache.maven.plugins:maven-plugin-plugin:3.3:descriptor failed: syntax error @[8,1] in file:/full/path/to/project/default-method/src/main/java/org/example/Iface.java -> [Help 1]

即使该文件Iface.java是可编译的.

Iface.java:

package org.example;

public interface Iface {
    default String getString() {
        return "string";
    }
}

maven-plugin


    
        
            org.apache.maven.plugins
            maven-compiler-plugin
            3.3
            
                1.8
                1.8
            
        
    



    
        org.apache.maven
        maven-plugin-api
        3.0.5
    
    
        org.apache.maven.plugin-tools
        maven-plugin-annotations
        3.4
        provided
    

    
        
            org.apache.maven.plugins
            maven-plugin-plugin
            3.4