the following steps can be followed.
1. navigate into the play project root directory. eg. C:\my-play-project
2. add the following plugin into the end of project/plugins.sbt
addSbtPlugin("com.typesafe.sbteclipse" % "sbteclipse-plugin" % "5.2.2")
3. add the following configuration into the end of build.sbt
EclipseKeys.preTasks := Seq(compile in Compile, compile in Test)
EclipseKeys.projectFlavor := EclipseProjectFlavor.Java
EclipseKeys.createSrc := EclipseCreateSrc.ValueSet(EclipseCreateSrc.ManagedClasses, EclipseCreateSrc.ManagedResources)