CODEWITHSUNDEEP
javaeclipsecompiler-errors
Anderson
Anderson

Reputation: 2752

Different compilation behavior with type cast between eclipse and maven

Here is my code example:

private static void fac(Map<? extends Serializable,? extends Serializable> mapTo){
    //do sth.
}

public static void main(String[] args) {
    Map<String,Object> mapFrom=null;
    fac((Map<? extends Serializable, ? extends Serializable>) mapFrom);     
}

The code above is compiled successfully in eclipse(with a type safety warning) but failed in maven(an "incompatible types" error caused by javac?).

Now I have to change my code like this:

public static void main(String[] args) {
    Map<String,Object> mapFrom=null;
    fac((Map) mapFrom);     
}

I've confirmed the java version is the same, and my question is:

  1. Why do they have different behavior?

  2. What's the preferred way to write the code?

Upvotes: 0

Views: 1670

Answers (2)

Aaron Digulla
Aaron Digulla

Reputation: 328614

Eclipse comes with its own Java compiler; Maven uses javac. Most of the time, both accept the same code but generics are complicated and compiler do have bugs. There are a couple of known bugs in javac of Java 6 which cause problems, for example.

Oracle will not fix them. The solution is to use Java 7 to run Maven and configure the maven-compiler-plugin the generate Java 6 byte code (see Kumar Sambhav's answer).

Upvotes: 1

Kumar Sambhav
Kumar Sambhav

Reputation: 7765

Try adding this plugin (inside build->plugins-> tag) to your pom.xml :-

        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-compiler-plugin</artifactId>
            <version>3.0</version>
            <configuration>
                <source>1.6</source>
                <target>1.6</target>
            </configuration>
        </plugin>

This will ensure the compiler version to be used with your project.

Upvotes: 0

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