added support for lsp-based hovers in JDT editor

eclipse-language-servers/org.springframework.boot.ide.java.servers/plugin.xml

@@ -25,5 +25,14 @@
             needsSortingAfterFiltering="false">
       </javaCompletionProposalComputer>
    </extension>
+   <extension
+         id="springbootjava-hover-provider"
+         point="org.eclipse.jdt.ui.javaEditorTextHovers">
+      <hover
+            activate="true"
+            class="org.springframework.boot.ide.java.servers.SpringBootJavaHoverProvider"
+            id="org.springframework.boot.ide.java.servers.hoverprovider">
+      </hover>
+   </extension>
 
 </plugin>

eclipse-language-servers/org.springframework.boot.ide.java.servers/src/org/springframework/boot/ide/java/servers/SpringBootJavaHoverProvider.java

@@ -0,0 +1,45 @@
+/*******************************************************************************
+ * Copyright (c) 2017 Pivotal, Inc.
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ *
+ * Contributors:
+ *     Pivotal, Inc. - initial API and implementation
+ *******************************************************************************/
+package org.springframework.boot.ide.java.servers;
+
+import org.eclipse.jdt.ui.text.java.hover.IJavaEditorTextHover;
+import org.eclipse.jface.text.IRegion;
+import org.eclipse.jface.text.ITextViewer;
+import org.eclipse.lsp4e.operations.hover.LSBasedHover;
+import org.eclipse.ui.IEditorPart;
+
+/**
+ * @author Martin Lippert
+ */
+@SuppressWarnings("restriction")
+public class SpringBootJavaHoverProvider implements IJavaEditorTextHover {
+	
+	private LSBasedHover lsBasedHover;
+
+	public SpringBootJavaHoverProvider() {
+		lsBasedHover = new LSBasedHover();
+	}
+
+	@Override
+	public String getHoverInfo(ITextViewer textViewer, IRegion hoverRegion) {
+		return this.lsBasedHover.getHoverInfo(textViewer, hoverRegion);
+	}
+
+	@Override
+	public IRegion getHoverRegion(ITextViewer textViewer, int offset) {
+		return this.lsBasedHover.getHoverRegion(textViewer, offset);
+	}
+
+	@Override
+	public void setEditor(IEditorPart editor) {
+	}
+
+}