DATACMNS-170 - Fixed potential NullPointerException in ReflectionEntityInstantiator.

Moved null-check before the attempt to make the discovered id field accessible.

spring-data-commons-core/src/main/java/org/springframework/data/repository/core/support/ReflectionEntityInformation.java

@@ -69,9 +69,8 @@ public class ReflectionEntityInformation<T, ID extends Serializable> extends Abs
 			}
 		});
 
-		ReflectionUtils.makeAccessible(field);
-
 		Assert.notNull(this.field, String.format("No field annotated with %s found!", annotation.toString()));
+		ReflectionUtils.makeAccessible(field);
 	}
 
 	/* 

spring-data-commons-core/src/test/java/org/springframework/data/repository/core/support/ReflectionEntityInformationUnitTests.java

@@ -0,0 +1,65 @@
+/*
+ * Copyright 2012 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may
+import java.io.Serializable;
+ not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.data.repository.core.support;
+
+import static org.hamcrest.Matchers.*;
+import static org.junit.Assert.*;
+
+import java.io.Serializable;
+
+import org.junit.Test;
+import org.springframework.data.annotation.Id;
+import org.springframework.data.repository.core.EntityInformation;
+
+/**
+ * Unit tests for {@link ReflectionEntityInformation}.
+ * 
+ * @author Oliver Gierke
+ */
+public class ReflectionEntityInformationUnitTests {
+
+	@Test
+	public void discoversAnnotationOnField() {
+
+		EntityInformation<Sample, Serializable> information = getEntityInformation(Sample.class);
+		assertThat(information.getIdType(), is(typeCompatibleWith(String.class)));
+	}
+
+	/**
+	 * @see DATACMNS-170
+	 */
+	@Test(expected = IllegalArgumentException.class)
+	public void rejectsTypeWithoutAnnotatedField() {
+		getEntityInformation(Unannotated.class);
+	}
+
+	private static <T> EntityInformation<T, Serializable> getEntityInformation(Class<T> type) {
+		return new ReflectionEntityInformation<T, Serializable>(type, Id.class);
+	}
+
+	static class Sample {
+
+		@Id
+		String id;
+	}
+
+	static class Unannotated {
+
+		String id;
+	}
+}