I have an existing Java project in Eclipse. I want to implement builds using gradle. I tried using the gradle eclipse plugin as given here but ran into numerous errors in E
The first couple of chapters of the Gradle User Guide, along with the many (Java) samples in the full Gradle distribution, should get you started. It doesn't matter all that much whether your current build is Eclipse or something else; to be successful with Gradle, you'll first have to master its fundamentals.
Once you have the Gradle command line build working, you can give the IDE integration another shot. Depending on your preferences, you can either generate IDE files with Gradle's Eclipse plugin (again see the samples in the full Gradle distribution), or use the Eclipse Gradle Integration for a more integrated IDE experience.
Check out the Gradle homepage for additional resources. When faced with a concrete question about Gradle's build language, consult the Gradle DSL Reference. A full-text search over the single-page Gradle User Guide can also be quite effective. Last but not least, make sure to visit the Gradle Forums.