相同的源代码，Eclipse构建成功，但Maven（javac）失败 [英] Same source code, Eclipse build success but Maven (javac) fails

问题描述

在使用Maven进行编译时遇到此错误：

Keep getting this error when compiling using Maven:

type parameters of <X>X cannot be determined; no unique maximal instance exists for type variable X with upper bounds int,java.lang.Object

干扰不能应用于原始类型。但是我认为从Java5开始，Boxing / unboxing机制在原始类型和包装类之间无缝地工作。

Generics type interference cannot be applied to primitive types. But I thought since Java5, boxing/unboxing mechanism works seamlessly between primitive types and wrapper classes.

在任何情况下，奇怪的是Eclipse不报告任何错误，愉快地编译。我使用JDK1.6.0_12。

In any case, the strange thing is Eclipse doesn't report any errors and happily compiles. I'm using JDK1.6.0_12. What could possibly be the problem here?

推荐答案

当你的代码是通用的，并且它调用另一个方法，通用返回类型。有时编译器会试图弄清楚如何解决方法调用/返回类型。

This issue can occur when your code is generic and it calls another method that has a generic return type. Sometimes the compiler gets confused trying to figure out how to resolve the method call / return type.

它可以通过添加一个显式转换到您的代码。

It can be resolved by adding an explicit cast to your code.

// Old code:
public T getValue() {
    return otherMethod();  // otherMethod has the signature: <RT> RT otherMethod() { ... }
}

// New code:
@SuppressWarnings("unchecked")
public T getValue() {
    return (T) otherMethod();   // the cast tells the compiler what to do.
}

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