Failure on build with Gradle on command line with an android studio project : Xlint error

It's a nice warning, not an error. To see the complete lint report you can add these lines to build.gradle:

allprojects {
    tasks.withType(JavaCompile) {
        options.compilerArgs << "-Xlint:deprecation"
    }
}

If you really want to get rid of those warnings:

1. Don't use deprecated API
2. Use @SuppressWarnings("deprecation")

This is fairly obvious from @shakalaca's answer, but if you have code old enough to get the deprecation warning, you may also have code old enough to use unchecked operations, e.g. a List without the parameterized type as in List<String>. This will get you an additional warning:

Note: Some input files use unchecked or unsafe operations.
Note: Recompile with -Xlint:unchecked for details.

You can just expand the compiler args block to include that as well:

allprojects {
    tasks.withType(JavaCompile) {
        options.compilerArgs << "-Xlint:deprecation" << "-Xlint:unchecked"
    }
}