what are the disadvantages of not using maven default layout?

can't we have our own custom layout with a modified POM开发者_如何学JAVA ..are there any other disadvantages other than complicated POM

I guess you mean the project directory layout:

Yes, this is entirely customizable (see the POM Reference).

Example:

<build>
    <sourceDirectory>sources</sourceDirectory>
    <directory>output</directory>
    <outputDirectory>${project.build.directory}/compiled-classes
    </outputDirectory>
</build>

This sets the source folder to sources, the target folder to output and the compiler output folder to output/compiled-classes.

If you need additional source folders, you can't specify them in the <build> element, but you can add them dynamically with the buildhelper plugin.

If you are using only well-behaved standard maven plugins, this should work as expected. However, there may be some plugins with hard-coded paths like src/main/java and target/classes. Your mileage may vary.