Enable more compiler warnings in Eclipse

Mostly copied from the Gerrit project.

Change-Id: I33941ab31226cc1bdca483369c57a774bee1ccc1
diff --git a/.settings/org.eclipse.jdt.core.prefs b/.settings/org.eclipse.jdt.core.prefs
index e14e27f..c2a4ef5 100644
--- a/.settings/org.eclipse.jdt.core.prefs
+++ b/.settings/org.eclipse.jdt.core.prefs
@@ -16,6 +16,7 @@
 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.doc.comment.support=enabled
 org.eclipse.jdt.core.compiler.problem.APILeak=warning
 org.eclipse.jdt.core.compiler.problem.annotationSuperInterface=warning
 org.eclipse.jdt.core.compiler.problem.assertIdentifier=error
@@ -40,12 +41,25 @@
 org.eclipse.jdt.core.compiler.problem.incompatibleNonInheritedInterfaceMethod=warning
 org.eclipse.jdt.core.compiler.problem.incompleteEnumSwitch=warning
 org.eclipse.jdt.core.compiler.problem.indirectStaticAccess=ignore
+org.eclipse.jdt.core.compiler.problem.invalidJavadoc=warning
+org.eclipse.jdt.core.compiler.problem.invalidJavadocTags=enabled
+org.eclipse.jdt.core.compiler.problem.invalidJavadocTagsDeprecatedRef=enabled
+org.eclipse.jdt.core.compiler.problem.invalidJavadocTagsNotVisibleRef=enabled
+org.eclipse.jdt.core.compiler.problem.invalidJavadocTagsVisibility=private
 org.eclipse.jdt.core.compiler.problem.localVariableHiding=warning
 org.eclipse.jdt.core.compiler.problem.methodWithConstructorName=warning
 org.eclipse.jdt.core.compiler.problem.missingDefaultCase=warning
 org.eclipse.jdt.core.compiler.problem.missingDeprecatedAnnotation=ignore
-org.eclipse.jdt.core.compiler.problem.missingEnumCaseDespiteDefault=disabled
-org.eclipse.jdt.core.compiler.problem.missingHashCodeMethod=ignore
+org.eclipse.jdt.core.compiler.problem.missingEnumCaseDespiteDefault=enabled
+org.eclipse.jdt.core.compiler.problem.missingHashCodeMethod=warning
+org.eclipse.jdt.core.compiler.problem.missingJavadocComments=ignore
+org.eclipse.jdt.core.compiler.problem.missingJavadocCommentsOverriding=disabled
+org.eclipse.jdt.core.compiler.problem.missingJavadocCommentsVisibility=public
+org.eclipse.jdt.core.compiler.problem.missingJavadocTagDescription=return_tag
+org.eclipse.jdt.core.compiler.problem.missingJavadocTags=ignore
+org.eclipse.jdt.core.compiler.problem.missingJavadocTagsMethodTypeParameters=disabled
+org.eclipse.jdt.core.compiler.problem.missingJavadocTagsOverriding=disabled
+org.eclipse.jdt.core.compiler.problem.missingJavadocTagsVisibility=protected
 org.eclipse.jdt.core.compiler.problem.missingOverrideAnnotation=warning
 org.eclipse.jdt.core.compiler.problem.missingOverrideAnnotationForInterfaceMethodImplementation=enabled
 org.eclipse.jdt.core.compiler.problem.missingSerialVersion=warning
@@ -88,10 +102,10 @@
 org.eclipse.jdt.core.compiler.problem.unlikelyCollectionMethodArgumentType=warning
 org.eclipse.jdt.core.compiler.problem.unlikelyCollectionMethodArgumentTypeStrict=disabled
 org.eclipse.jdt.core.compiler.problem.unlikelyEqualsArgumentType=warning
-org.eclipse.jdt.core.compiler.problem.unnecessaryElse=ignore
-org.eclipse.jdt.core.compiler.problem.unnecessaryTypeCheck=ignore
+org.eclipse.jdt.core.compiler.problem.unnecessaryElse=warning
+org.eclipse.jdt.core.compiler.problem.unnecessaryTypeCheck=warning
 org.eclipse.jdt.core.compiler.problem.unqualifiedFieldAccess=ignore
-org.eclipse.jdt.core.compiler.problem.unusedDeclaredThrownException=ignore
+org.eclipse.jdt.core.compiler.problem.unusedDeclaredThrownException=warning
 org.eclipse.jdt.core.compiler.problem.unusedDeclaredThrownExceptionExemptExceptionAndThrowable=enabled
 org.eclipse.jdt.core.compiler.problem.unusedDeclaredThrownExceptionIncludeDocCommentReference=enabled
 org.eclipse.jdt.core.compiler.problem.unusedDeclaredThrownExceptionWhenOverriding=disabled
@@ -100,7 +114,7 @@
 org.eclipse.jdt.core.compiler.problem.unusedLabel=warning
 org.eclipse.jdt.core.compiler.problem.unusedLocal=warning
 org.eclipse.jdt.core.compiler.problem.unusedObjectAllocation=warning
-org.eclipse.jdt.core.compiler.problem.unusedParameter=ignore
+org.eclipse.jdt.core.compiler.problem.unusedParameter=warning
 org.eclipse.jdt.core.compiler.problem.unusedParameterIncludeDocCommentReference=enabled
 org.eclipse.jdt.core.compiler.problem.unusedParameterWhenImplementingAbstract=disabled
 org.eclipse.jdt.core.compiler.problem.unusedParameterWhenOverridingConcrete=disabled
@@ -108,4 +122,5 @@
 org.eclipse.jdt.core.compiler.problem.unusedTypeParameter=ignore
 org.eclipse.jdt.core.compiler.problem.unusedWarningToken=warning
 org.eclipse.jdt.core.compiler.problem.varargsArgumentNeedCast=warning
+org.eclipse.jdt.core.compiler.processAnnotations=enabled
 org.eclipse.jdt.core.compiler.source=1.8