DATACMNS-855 - Prevent memory leak in SyntheticParameterizedType.

Added proper equals(…) and hashCode() methods to SyntheticParameterizedType to make sure instances created for the same type information and type parameters are considered equal.

src/main/java/org/springframework/data/util/TypeDiscoverer.java

@@ -609,5 +609,40 @@ class TypeDiscoverer<S> implements TypeInformation<S> {
 
 			return result;
 		}
+
+		/* 
+		 * (non-Javadoc)
+		 * @see java.lang.Object#equals(java.lang.Object)
+		 */
+		@Override
+		public boolean equals(Object obj) {
+
+			if (this == obj) {
+				return true;
+			}
+
+			if (!(obj instanceof SyntheticParamterizedType)) {
+				return false;
+			}
+
+			SyntheticParamterizedType that = (SyntheticParamterizedType) obj;
+
+			return this.typeInformation.equals(that.typeInformation) && this.typeParameters.equals(that.typeParameters);
+		}
+
+		/* 
+		 * (non-Javadoc)
+		 * @see java.lang.Object#hashCode()
+		 */
+		@Override
+		public int hashCode() {
+
+			int result = 17;
+
+			result += 31 * typeInformation.hashCode();
+			result += 31 * typeParameters.hashCode();
+
+			return result;
+		}
 	}
 }

src/test/java/org/springframework/data/util/ClassTypeInformationUnitTests.java

@@ -382,6 +382,24 @@ public class ClassTypeInformationUnitTests {
 		assertThat(property.specialize(from), is((TypeInformation) from));
 	}
 
+	/**
+	 * @see DATACMNS-855
+	 */
+	@Test
+	@SuppressWarnings("rawtypes")
+	public void specializedTypeEqualsAndHashCode() {
+
+		ClassTypeInformation<Foo> root = ClassTypeInformation.from(Foo.class);
+		TypeInformation<?> property = root.getProperty("abstractBar");
+
+		TypeInformation left = property.specialize(ClassTypeInformation.from(Bar.class));
+		TypeInformation right = property.specialize(ClassTypeInformation.from(Bar.class));
+
+		assertThat(left, is(right));
+		assertThat(right, is(left));
+		assertThat(left.hashCode(), is(right.hashCode()));
+	}
+
 	static class StringMapContainer extends MapContainer<String> {
 
 	}