是否是eclipse或maven-compiler-plugin错误，泛型类转换问题？ [英] Is it an eclipse or maven-compiler-plugin bug, the generics Class cast issue?

问题描述

我有一个这样的代码：

  protected< T> T doSomething（String someParam，Class< T> clazz）{
 ... 
} 
  

我在TestCase类中使用：

 类clazz = MyClass.class; 
 MyClass MyClass = someObject.doSomething（someString，clazz）; 
  

此代码在eclipse中发出警告：

类是一个原始类型。参考泛型类应该参数化

和

此行上的多个标记

- 类型安全性：未检查的调用类型MyClass的通用方法doSomething（String，Class）的doSomething（String，Class）

- 类型安全性：类型类的表达式需要未经检查的转换才能符合Class

当我在eclipse中运行此代码（测试） - 一切都很完美。当我通过mvn clean install通过命令提示符进行操作时，我得到：

C：\pathToProject\ src\test\java\packagesPath\MyTestCase.java：找到不兼容类型的[xx，xxx]：

java.lang.Object

required：com.somePackagePath。 MyClass

但是提供时：

 类< MyClass的> clazz = MyClass.class; 
 MyClass MyClass = someObject.doSomething（someString，clazz）; 
  

我没有收到任何错误或警告。。

我明白java编译器擦除类型信息，所以：

不应该eclipse提供编译器错误而不是警告，还是maven-plugin-compiler是否会产生问题？ br>
maven插件是：

 < plugin> 
< groupId> org.apache.maven.plugins< / groupId> 
< artifactId> maven-compiler-plugin< / artifactId> 
< configuration> 
< source> 1.6< / source> 
< target> 1.6< / target> 
< showDeprecation> false< / showDeprecation> 
< debug> true< / debug> 
< encoding> UTF-8< / encoding> 
< / configuration> 
< / plugin> 
  

请问，

Despot

解决方案

这是Eclipse中的一个已知错误： 333011：[编译器] [1.5] Eclipse编译javac拒绝的代码：不兼容的类型。可以自由地投票支持该错误，并添加您的用例。

---

有些情况下 javac 和Eclipse不同意，您应该将其报告为错误。优选的是具有尽可能少的Java文件的独立测试用例，它们可以在Eclipse中复制/粘贴，并使用命令行中的 javac 进行编译，而无需依赖。 / p>

I have a code like this:

protected <T> T doSomething(String someParam, Class<T> clazz) {
...
}

which I use in a TestCase class:

Class clazz = MyClass.class;
MyClass MyClass = someObject.doSomething(someString, clazz);

This code gives a warning in eclipse:

Class is a raw type. References to generic type Class should be parameterized

and

Multiple markers at this line
- Type safety: Unchecked invocation doSomething(String, Class) of the generic method doSomething(String, Class) of type MyClass
- Type safety: The expression of type Class needs unchecked conversion to conform to Class

When I run this code (test) in eclipse - everything works perfectly. When I do it through "mvn clean install" through command prompt, I get:

C:\pathToProject\src\test\java\packagesPath\MyTestCase.java:[xx,xxx] incompatible types found :
java.lang.Object
required: com.somePackagePath.MyClass

But when providing:

Class<MyClass> clazz = MyClass.class;
MyClass MyClass = someObject.doSomething(someString, clazz);

I don't get any errors nor warnings. .
I understand that java compiler erases type info, so:
Shouldn't eclipse provide a compiler error instead of warning, or is it the maven-plugin-compiler that creates the problem?
The maven plugin is:

        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-compiler-plugin</artifactId>
            <configuration>
                <source>1.6</source>
                <target>1.6</target>
                <showDeprecation>false</showDeprecation>
                <debug>true</debug>
                <encoding>UTF-8</encoding>
            </configuration>
        </plugin>

Kind Regards,
Despot

解决方案

This is a known bug in Eclipse: 333011: [compiler][1.5] Eclipse compiles codes which javac rejects: incompatible types . Feel free to vote for the bug and add your use case to it.

---

There are situations when javac and Eclipse disagree, and you should report them as bugs. It is preferred to have a standalone test case of as few Java files as possible which can be copy/pasted in Eclipse and compiled using javac from the command line without any dependencies.

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