make ES compile with java 8

- that isAnnotationPresent bug is known, and probably will be fixed in later versions, but it costs us nothing to not use it now
- some tests fail, mainly due to consistent ordering expected from Map (within versions) which does not seem to be preserved, need to fix those tests to be agnostic to it

src/main/java/org/elasticsearch/common/inject/Key.java

@@ -506,6 +506,6 @@ public class Key<T> {
 
     static boolean isBindingAnnotation(
             Class<? extends Annotation> annotationType) {
-        return annotationType.isAnnotationPresent(BindingAnnotation.class);
+        return annotationType.getAnnotation(BindingAnnotation.class) != null;
     }
 }

src/main/java/org/elasticsearch/common/inject/internal/Annotations.java

@@ -56,7 +56,7 @@ public class Annotations {
         Class<? extends Annotation> found = null;
 
         for (Annotation annotation : annotations) {
-            if (annotation.annotationType().isAnnotationPresent(ScopeAnnotation.class)) {
+            if (annotation.annotationType().getAnnotation(ScopeAnnotation.class) != null) {
                 if (found != null) {
                     errors.duplicateScopeAnnotations(found, annotation.annotationType());
                 } else {
@@ -69,7 +69,7 @@ public class Annotations {
     }
 
     public static boolean isScopeAnnotation(Class<? extends Annotation> annotationType) {
-        return annotationType.isAnnotationPresent(ScopeAnnotation.class);
+        return annotationType.getAnnotation(ScopeAnnotation.class) != null;
     }
 
     /**
@@ -107,7 +107,7 @@ public class Annotations {
         Annotation found = null;
 
         for (Annotation annotation : annotations) {
-            if (annotation.annotationType().isAnnotationPresent(BindingAnnotation.class)) {
+            if (annotation.annotationType().getAnnotation(BindingAnnotation.class) != null) {
                 if (found != null) {
                     errors.duplicateBindingAnnotations(member,
                             found.annotationType(), annotation.annotationType());

src/main/java/org/elasticsearch/common/inject/internal/ProviderMethod.java

@@ -53,7 +53,7 @@ public class ProviderMethod<T> implements ProviderWithDependencies<T> {
         this.dependencies = dependencies;
         this.method = method;
         this.parameterProviders = parameterProviders;
-        this.exposed = method.isAnnotationPresent(Exposed.class);
+        this.exposed = method.getAnnotation(Exposed.class) != null;
 
         method.setAccessible(true);
     }

src/main/java/org/elasticsearch/common/inject/internal/ProviderMethodsModule.java

@@ -76,7 +76,7 @@ public final class ProviderMethodsModule implements Module {
         List<ProviderMethod<?>> result = Lists.newArrayList();
         for (Class<?> c = delegate.getClass(); c != Object.class; c = c.getSuperclass()) {
             for (Method method : c.getDeclaredMethods()) {
-                if (method.isAnnotationPresent(Provides.class)) {
+                if (method.getAnnotation(Provides.class) != null) {
                     result.add(createProviderMethod(binder, method));
                 }
             }

src/main/java/org/elasticsearch/common/inject/spi/DefaultBindingTargetVisitor.java

@@ -71,6 +71,6 @@ public abstract class DefaultBindingTargetVisitor<T, V> implements BindingTarget
     // javac says it's an error to cast ProviderBinding<? extends T> to Binding<? extends T>
     @SuppressWarnings("unchecked")
     public V visit(ProviderBinding<? extends T> providerBinding) {
-        return visitOther((Binding) providerBinding);
+        return visitOther((Binding<? extends T>) providerBinding);
     }
 }