Yes, your program must also be GPL.
GPL is quite clear on this matter: if your program links to a GPL library, no matter the type of linking, then your program also comes under the GPL (when you distribute). LGPL adds a dynamic linking exception, but this doesn't apply in your case.
With Java it's no different; if your program links with a GPL .jar, it is considered a derivative as far as the GPL is concerned. LGPL also works as intended with Java.
The typical arrangement for Java is that each library an application uses is distributed as a separate JAR (Java Archive) file. Applications use Java's “import” functionality to access classes from these libraries. When the application is compiled, function signatures are checked against the library, creating a link. The application is then generally a derivative work of the library. So, the copyright holder for the library must authorize distribution of the work. The LGPL permits this distribution.
So in your Java project, if it ever includes a .jar that is GPL, or you type in "import foobar" where foobar is GPL, then your program is also affected.