Source is not 1.7 any more (#3587)

* fix warning

* fix warning

* Java 1.8

Author: elharo

third_party/com.google.cloud.tools.eclipse.jst.server.core/build.properties

@@ -5,5 +5,5 @@ bin.includes = META-INF/,\
                plugin.properties,\
                epl-v10.html,\
                README.md
-javacSource=1.7
-javacTarget=1.7               
+javacSource=1.8
+javacTarget=1.8               

third_party/com.google.cloud.tools.eclipse.jst.server.core/org.eclipse.jdt.core.prefs

@@ -11,15 +11,15 @@ org.eclipse.jdt.core.codeComplete.staticFinalFieldPrefixes=
 org.eclipse.jdt.core.codeComplete.staticFinalFieldSuffixes=
 org.eclipse.jdt.core.compiler.codegen.inlineJsrBytecode=enabled
 org.eclipse.jdt.core.compiler.codegen.methodParameters=do not generate
-org.eclipse.jdt.core.compiler.codegen.targetPlatform=1.7
+org.eclipse.jdt.core.compiler.codegen.targetPlatform=1.8
 org.eclipse.jdt.core.compiler.codegen.unusedLocal=preserve
-org.eclipse.jdt.core.compiler.compliance=1.7
+org.eclipse.jdt.core.compiler.compliance=1.8
 org.eclipse.jdt.core.compiler.debug.lineNumber=generate
 org.eclipse.jdt.core.compiler.debug.localVariable=generate
 org.eclipse.jdt.core.compiler.debug.sourceFile=generate
 org.eclipse.jdt.core.compiler.problem.assertIdentifier=error
 org.eclipse.jdt.core.compiler.problem.enumIdentifier=error
-org.eclipse.jdt.core.compiler.source=1.7
+org.eclipse.jdt.core.compiler.source=1.8
 org.eclipse.jdt.core.formatter.align_fields_grouping_blank_lines=2147483647
 org.eclipse.jdt.core.formatter.align_type_members_on_columns=false
 org.eclipse.jdt.core.formatter.alignment_for_arguments_in_allocation_expression=16