Postgres JDBC Error in Eclipse

I'm trying to do a project to test the connection in the PostgreSQL database (I'm using version 9.2) in Eclipse (Mars Version). I'm using postgresql-9.2-1004.jdbc3 and adding it to Build Path. However, when trying to execute the class to test the connection, a match message appears and asks to choose a class that is in the JDBC package and the test class. When you try to run the test class, it says that the connection attempt failed. How should I proceed?