Ahora funciona

.classpath

 <?xml version="1.0" encoding="UTF-8"?>
 <classpath>
-	<classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER/org.eclipse.jdt.internal.debug.ui.launcher.StandardVMType/JavaSE-10">
-		<attributes>
-			<attribute name="module" value="true"/>
-		</attributes>
-	</classpathentry>
 	<classpathentry kind="src" path="src"/>
+	<classpathentry exported="true" kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER/org.eclipse.jdt.internal.debug.ui.launcher.StandardVMType/JavaSE-1.8"/>
 	<classpathentry kind="output" path="bin"/>
 </classpath>

.settings/org.eclipse.jdt.core.prefs

 eclipse.preferences.version=1
+org.eclipse.jdt.core.codeComplete.argumentPrefixes=
+org.eclipse.jdt.core.codeComplete.argumentSuffixes=
+org.eclipse.jdt.core.codeComplete.fieldPrefixes=
+org.eclipse.jdt.core.codeComplete.fieldSuffixes=
+org.eclipse.jdt.core.codeComplete.localPrefixes=
+org.eclipse.jdt.core.codeComplete.localSuffixes=
+org.eclipse.jdt.core.codeComplete.staticFieldPrefixes=
+org.eclipse.jdt.core.codeComplete.staticFieldSuffixes=
+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.targetPlatform=10
+org.eclipse.jdt.core.compiler.codegen.methodParameters=do not generate
+org.eclipse.jdt.core.compiler.codegen.targetPlatform=1.8
 org.eclipse.jdt.core.compiler.codegen.unusedLocal=preserve
-org.eclipse.jdt.core.compiler.compliance=10
+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.release=enabled
-org.eclipse.jdt.core.compiler.source=10
+org.eclipse.jdt.core.compiler.release=disabled
+org.eclipse.jdt.core.compiler.source=1.8

.settings/org.eclipse.jdt.ui.prefs

+eclipse.preferences.version=1
+org.eclipse.jdt.ui.exception.name=e
+org.eclipse.jdt.ui.gettersetter.use.is=true
+org.eclipse.jdt.ui.keywordthis=false
+org.eclipse.jdt.ui.overrideannotation=true