Question

I’m using maven to build the project and compile failed because I put class Test2 in Test.java,

but is it because of maven or simply because java itself doesn’t support this?

BTW,how can I open a maven project with eclipse?

Answer 1

A public class called ClassName must (in most cases) be defined in a file called ClassName.java.

Edit

Although this is not a requirement of the Java language, most (if not all) implementations of Java, the above mentioned relationship between the class name and file name must hold, or a compiler error will result.

(For more information, please refer to Jon Skeet’s answer.)

The reason for this can be found by reading Section 7.2: Packages of The Java Language Specification, Third Edition.

In the section, it describes how the directory structure can be mapped to a fully-qualified class name in Java, which leads to a requirement that the .class file which contains the bytecode for a class must reside in a path that resembles that of the fully-qualified class name.

The original answer which incorrectly stated that the naming scheme is a requirement has been edited.