diff --git a/spring-expression/src/main/java/org/springframework/expression/Expression.java b/spring-expression/src/main/java/org/springframework/expression/Expression.java
index 98982967bc..2be2d0319f 100644
--- a/spring-expression/src/main/java/org/springframework/expression/Expression.java
+++ b/spring-expression/src/main/java/org/springframework/expression/Expression.java
@@ -20,18 +20,19 @@ import org.springframework.core.convert.TypeDescriptor;
 import org.springframework.lang.Nullable;
 
 /**
- * An expression capable of evaluating itself against context objects. Encapsulates the
- * details of a previously parsed expression string. Provides a common abstraction for
- * expression evaluation independent of any language like OGNL or the Unified EL.
+ * An expression capable of evaluating itself against context objects.
+ * Encapsulates the details of a previously parsed expression string.
+ * Provides a common abstraction for expression evaluation.
  *
  * @author Keith Donald
  * @author Andy Clement
+ * @author Juergen Hoeller
  * @since 3.0
  */
 public interface Expression {
 
 	/**
-	 * Return the original string used to create this expression, unmodified.
+	 * Return the original string used to create this expression (unmodified).
 	 * @return the original expression string
 	 */
 	String getExpressionString();
@@ -45,8 +46,9 @@ public interface Expression {
 	Object getValue() throws EvaluationException;
 
 	/**
-	 * Evaluate the expression in the default context. If the result of the evaluation does not match (and
-	 * cannot be converted to) the expected result type then an exception will be returned.
+	 * Evaluate the expression in the default context. If the result
+	 * of the evaluation does not match (and cannot be converted to)
+	 * the expected result type then an exception will be returned.
 	 * @param desiredResultType the class the caller would like the result to be
 	 * @return the evaluation result
 	 * @throws EvaluationException if there is a problem during evaluation
@@ -55,8 +57,8 @@ public interface Expression {
 	<T> T getValue(@Nullable Class<T> desiredResultType) throws EvaluationException;
 
 	/**
-	 * Evaluate this expression against the specified root object
-	 * @param rootObject the root object against which properties/etc will be resolved
+	 * Evaluate this expression against the specified root object.
+	 * @param rootObject the root object against which to evaluate the expression
 	 * @return the evaluation result
 	 * @throws EvaluationException if there is a problem during evaluation
 	 */
@@ -64,10 +66,10 @@ public interface Expression {
 	Object getValue(Object rootObject) throws EvaluationException;
 
 	/**
-	 * Evaluate the expression in the default context against the specified root object. If the
-	 * result of the evaluation does not match (and cannot be converted to) the expected result type
-	 * then an exception will be returned.
-	 * @param rootObject the root object against which properties/etc will be resolved
+	 * Evaluate the expression in the default context against the specified root
+	 * object. If the result of the evaluation does not match (and cannot be
+	 * converted to) the expected result type then an exception will be returned.
+	 * @param rootObject the root object against which to evaluate the expression
 	 * @param desiredResultType the class the caller would like the result to be
 	 * @return the evaluation result
 	 * @throws EvaluationException if there is a problem during evaluation
@@ -76,7 +78,8 @@ public interface Expression {
 	<T> T getValue(Object rootObject, @Nullable Class<T> desiredResultType) throws EvaluationException;
 
 	/**
-	 * Evaluate this expression in the provided context and return the result of evaluation.
+	 * Evaluate this expression in the provided context and return the result
+	 * of evaluation.
 	 * @param context the context in which to evaluate the expression
 	 * @return the evaluation result
 	 * @throws EvaluationException if there is a problem during evaluation
@@ -85,10 +88,11 @@ public interface Expression {
 	Object getValue(EvaluationContext context) throws EvaluationException;
 
 	/**
-	 * Evaluate this expression in the provided context and return the result of evaluation, but use
-	 * the supplied root context as an override for any default root object specified in the context.
+	 * Evaluate this expression in the provided context and return the result
+	 * of evaluation, but use the supplied root context as an override for any
+	 * default root object specified in the context.
 	 * @param context the context in which to evaluate the expression
-	 * @param rootObject the root object against which properties/etc will be resolved
+	 * @param rootObject the root object against which to evaluate the expression
 	 * @return the evaluation result
 	 * @throws EvaluationException if there is a problem during evaluation
 	 */
@@ -96,8 +100,9 @@ public interface Expression {
 	Object getValue(EvaluationContext context, Object rootObject) throws EvaluationException;
 
 	/**
-	 * Evaluate the expression in a specified context which can resolve references to properties, methods, types, etc -
-	 * the type of the evaluation result is expected to be of a particular class and an exception will be thrown if it
+	 * Evaluate the expression in a specified context which can resolve references
+	 * to properties, methods, types, etc. The type of the evaluation result is
+	 * expected to be of a particular class and an exception will be thrown if it
 	 * is not and cannot be converted to that type.
 	 * @param context the context in which to evaluate the expression
 	 * @param desiredResultType the class the caller would like the result to be
@@ -108,12 +113,13 @@ public interface Expression {
 	<T> T getValue(EvaluationContext context, @Nullable Class<T> desiredResultType) throws EvaluationException;
 
 	/**
-	 * Evaluate the expression in a specified context which can resolve references to properties, methods, types, etc -
-	 * the type of the evaluation result is expected to be of a particular class and an exception will be thrown if it
-	 * is not and cannot be converted to that type.  The supplied root object overrides any default specified on the
-	 * supplied context.
+	 * Evaluate the expression in a specified context which can resolve references
+	 * to properties, methods, types, etc. The type of the evaluation result is
+	 * expected to be of a particular class and an exception will be thrown if it
+	 * is not and cannot be converted to that type. The supplied root object
+	 * overrides any default specified on the supplied context.
 	 * @param context the context in which to evaluate the expression
-	 * @param rootObject the root object against which properties/etc will be resolved
+	 * @param rootObject the root object against which to evaluate the expression
 	 * @param desiredResultType the class the caller would like the result to be
 	 * @return the evaluation result
 	 * @throws EvaluationException if there is a problem during evaluation
@@ -123,7 +129,7 @@ public interface Expression {
 			throws EvaluationException;
 
 	/**
-	 * Returns the most general type that can be passed to the {@link #setValue(EvaluationContext, Object)}
+	 * Return the most general type that can be passed to a {@link #setValue}
 	 * method using the default context.
 	 * @return the most general type of value that can be set on this context
 	 * @throws EvaluationException if there is a problem determining the type
@@ -132,8 +138,8 @@ public interface Expression {
 	Class<?> getValueType() throws EvaluationException;
 
 	/**
-	 * Returns the most general type that can be passed to the {@link #setValue(EvaluationContext, Object)}
-	 * method using the default context.
+	 * Return the most general type that can be passed to the
+	 * {@link #setValue(Object, Object)} method using the default context.
 	 * @param rootObject the root object against which to evaluate the expression
 	 * @return the most general type of value that can be set on this context
 	 * @throws EvaluationException if there is a problem determining the type
@@ -142,8 +148,8 @@ public interface Expression {
 	Class<?> getValueType(Object rootObject) throws EvaluationException;
 
 	/**
-	 * Returns the most general type that can be passed to the {@link #setValue(EvaluationContext, Object)}
-	 * method for the given context.
+	 * Return the most general type that can be passed to the
+	 * {@link #setValue(EvaluationContext, Object)} method for the given context.
 	 * @param context the context in which to evaluate the expression
 	 * @return the most general type of value that can be set on this context
 	 * @throws EvaluationException if there is a problem determining the type
@@ -152,8 +158,9 @@ public interface Expression {
 	Class<?> getValueType(EvaluationContext context) throws EvaluationException;
 
 	/**
-	 * Returns the most general type that can be passed to the {@link #setValue(EvaluationContext, Object)}
-	 * method for the given context. The supplied root object overrides any specified in the context.
+	 * Return the most general type that can be passed to the
+	 * {@link #setValue(EvaluationContext, Object, Object)} method for the given
+	 * context. The supplied root object overrides any specified in the context.
 	 * @param context the context in which to evaluate the expression
 	 * @param rootObject the root object against which to evaluate the expression
 	 * @return the most general type of value that can be set on this context
@@ -163,40 +170,41 @@ public interface Expression {
 	Class<?> getValueType(EvaluationContext context, Object rootObject) throws EvaluationException;
 
 	/**
-	 * Returns the most general type that can be passed to the {@link #setValue(EvaluationContext, Object)}
+	 * Return the most general type that can be passed to a {@link #setValue}
 	 * method using the default context.
-	 * @return a type descriptor for the most general type of value that can be set on this context
+	 * @return a type descriptor for values that can be set on this context
 	 * @throws EvaluationException if there is a problem determining the type
 	 */
 	@Nullable
 	TypeDescriptor getValueTypeDescriptor() throws EvaluationException;
 
 	/**
-	 * Returns the most general type that can be passed to the {@link #setValue(EvaluationContext, Object)}
-	 * method using the default context.
+	 * Return the most general type that can be passed to the
+	 * {@link #setValue(Object, Object)} method using the default context.
 	 * @param rootObject the root object against which to evaluate the expression
-	 * @return a type descriptor for the most general type of value that can be set on this context
+	 * @return a type descriptor for values that can be set on this context
 	 * @throws EvaluationException if there is a problem determining the type
 	 */
 	@Nullable
 	TypeDescriptor getValueTypeDescriptor(Object rootObject) throws EvaluationException;
 
 	/**
-	 * Returns the most general type that can be passed to the {@link #setValue(EvaluationContext, Object)}
-	 * method for the given context.
+	 * Return the most general type that can be passed to the
+	 * {@link #setValue(EvaluationContext, Object)} method for the given context.
 	 * @param context the context in which to evaluate the expression
-	 * @return a type descriptor for the most general type of value that can be set on this context
+	 * @return a type descriptor for values that can be set on this context
 	 * @throws EvaluationException if there is a problem determining the type
 	 */
 	@Nullable
 	TypeDescriptor getValueTypeDescriptor(EvaluationContext context) throws EvaluationException;
 
 	/**
-	 * Returns the most general type that can be passed to the {@link #setValue(EvaluationContext, Object)}
-	 * method for the given context. The supplied root object overrides any specified in the context.
+	 * Return the most general type that can be passed to the
+	 * {@link #setValue(EvaluationContext, Object, Object)} method for the given
+	 * context. The supplied root object overrides any specified in the context.
 	 * @param context the context in which to evaluate the expression
 	 * @param rootObject the root object against which to evaluate the expression
-	 * @return a type descriptor for the most general type of value that can be set on this context
+	 * @return a type descriptor for values that can be set on this context
 	 * @throws EvaluationException if there is a problem determining the type
 	 */
 	@Nullable
@@ -205,7 +213,7 @@ public interface Expression {
 	/**
 	 * Determine if an expression can be written to, i.e. setValue() can be called.
 	 * @param rootObject the root object against which to evaluate the expression
-	 * @return true if the expression is writable
+	 * @return {@code true} if the expression is writable; {@code false} otherwise
 	 * @throws EvaluationException if there is a problem determining if it is writable
 	 */
 	boolean isWritable(Object rootObject) throws EvaluationException;
@@ -213,7 +221,7 @@ public interface Expression {
 	/**
 	 * Determine if an expression can be written to, i.e. setValue() can be called.
 	 * @param context the context in which the expression should be checked
-	 * @return true if the expression is writable
+	 * @return {@code true} if the expression is writable; {@code false} otherwise
 	 * @throws EvaluationException if there is a problem determining if it is writable
 	 */
 	boolean isWritable(EvaluationContext context) throws EvaluationException;
@@ -223,7 +231,7 @@ public interface Expression {
 	 * The supplied root object overrides any specified in the context.
 	 * @param context the context in which the expression should be checked
 	 * @param rootObject the root object against which to evaluate the expression
-	 * @return true if the expression is writable
+	 * @return {@code true} if the expression is writable; {@code false} otherwise
 	 * @throws EvaluationException if there is a problem determining if it is writable
 	 */
 	boolean isWritable(EvaluationContext context, Object rootObject) throws EvaluationException;
diff --git a/spring-expression/src/main/java/org/springframework/expression/spel/standard/SpelExpression.java b/spring-expression/src/main/java/org/springframework/expression/spel/standard/SpelExpression.java
index 181ab03cee..ae895ce288 100644
--- a/spring-expression/src/main/java/org/springframework/expression/spel/standard/SpelExpression.java
+++ b/spring-expression/src/main/java/org/springframework/expression/spel/standard/SpelExpression.java
@@ -115,7 +115,6 @@ public class SpelExpression implements Expression {
 
 	@Override
 	public Object getValue() throws EvaluationException {
-		Object result;
 		if (this.compiledAst != null) {
 			try {
 				TypedValue contextRoot =
@@ -135,8 +134,9 @@ public class SpelExpression implements Expression {
 				}
 			}
 		}
+
 		ExpressionState expressionState = new ExpressionState(getEvaluationContext(), this.configuration);
-		result = this.ast.getValue(expressionState);
+		Object result = this.ast.getValue(expressionState);
 		checkCompile(expressionState);
 		return result;
 	}
@@ -170,6 +170,7 @@ public class SpelExpression implements Expression {
 				}
 			}
 		}
+
 		ExpressionState expressionState = new ExpressionState(getEvaluationContext(), this.configuration);
 		TypedValue typedResultValue = this.ast.getTypedValue(expressionState);
 		checkCompile(expressionState);
@@ -179,7 +180,6 @@ public class SpelExpression implements Expression {
 
 	@Override
 	public Object getValue(Object rootObject) throws EvaluationException {
-		Object result;
 		if (this.compiledAst != null) {
 			try {
 				return this.compiledAst.getValue(rootObject, evaluationContext);
@@ -196,9 +196,10 @@ public class SpelExpression implements Expression {
 				}
 			}
 		}
+
 		ExpressionState expressionState =
 				new ExpressionState(getEvaluationContext(), toTypedValue(rootObject), this.configuration);
-		result = this.ast.getValue(expressionState);
+		Object result = this.ast.getValue(expressionState);
 		checkCompile(expressionState);
 		return result;
 	}
@@ -229,6 +230,7 @@ public class SpelExpression implements Expression {
 				}
 			}
 		}
+
 		ExpressionState expressionState =
 				new ExpressionState(getEvaluationContext(), toTypedValue(rootObject), this.configuration);
 		TypedValue typedResultValue = this.ast.getTypedValue(expressionState);
@@ -240,7 +242,8 @@ public class SpelExpression implements Expression {
 	@Override
 	public Object getValue(EvaluationContext context) throws EvaluationException {
 		Assert.notNull(context, "EvaluationContext is required");
-		if (compiledAst!= null) {
+
+		if (this.compiledAst != null) {
 			try {
 				TypedValue contextRoot = context.getRootObject();
 				return this.compiledAst.getValue(contextRoot.getValue(), context);
@@ -257,6 +260,7 @@ public class SpelExpression implements Expression {
 				}
 			}
 		}
+
 		ExpressionState expressionState = new ExpressionState(context, this.configuration);
 		Object result = this.ast.getValue(expressionState);
 		checkCompile(expressionState);
@@ -266,6 +270,8 @@ public class SpelExpression implements Expression {
 	@SuppressWarnings("unchecked")
 	@Override
 	public <T> T getValue(EvaluationContext context, @Nullable Class<T> expectedResultType) throws EvaluationException {
+		Assert.notNull(context, "EvaluationContext is required");
+
 		if (this.compiledAst != null) {
 			try {
 				TypedValue contextRoot = context.getRootObject();
@@ -289,6 +295,7 @@ public class SpelExpression implements Expression {
 				}
 			}
 		}
+
 		ExpressionState expressionState = new ExpressionState(context, this.configuration);
 		TypedValue typedResultValue = this.ast.getTypedValue(expressionState);
 		checkCompile(expressionState);
@@ -298,6 +305,7 @@ public class SpelExpression implements Expression {
 	@Override
 	public Object getValue(EvaluationContext context, Object rootObject) throws EvaluationException {
 		Assert.notNull(context, "EvaluationContext is required");
+
 		if (this.compiledAst != null) {
 			try {
 				return this.compiledAst.getValue(rootObject,context);
@@ -314,6 +322,7 @@ public class SpelExpression implements Expression {
 				}
 			}
 		}
+
 		ExpressionState expressionState = new ExpressionState(context, toTypedValue(rootObject), this.configuration);
 		Object result = this.ast.getValue(expressionState);
 		checkCompile(expressionState);
@@ -325,9 +334,11 @@ public class SpelExpression implements Expression {
 	public <T> T getValue(EvaluationContext context, Object rootObject, @Nullable Class<T> expectedResultType)
 			throws EvaluationException {
 
+		Assert.notNull(context, "EvaluationContext is required");
+
 		if (this.compiledAst != null) {
 			try {
-				Object result = this.compiledAst.getValue(rootObject,context);
+				Object result = this.compiledAst.getValue(rootObject, context);
 				if (expectedResultType != null) {
 					return ExpressionUtils.convertTypedValue(context, new TypedValue(result), expectedResultType);
 				}
@@ -347,6 +358,7 @@ public class SpelExpression implements Expression {
 				}
 			}
 		}
+
 		ExpressionState expressionState = new ExpressionState(context, toTypedValue(rootObject), this.configuration);
 		TypedValue typedResultValue = this.ast.getTypedValue(expressionState);
 		checkCompile(expressionState);
diff --git a/spring-expression/src/test/java/org/springframework/expression/spel/SpelCompilationCoverageTests.java b/spring-expression/src/test/java/org/springframework/expression/spel/SpelCompilationCoverageTests.java
index 162e078d2d..29c1b6cc5b 100644
--- a/spring-expression/src/test/java/org/springframework/expression/spel/SpelCompilationCoverageTests.java
+++ b/spring-expression/src/test/java/org/springframework/expression/spel/SpelCompilationCoverageTests.java
@@ -335,14 +335,14 @@ public class SpelCompilationCoverageTests extends AbstractExpressionTests {
 		// See SpelCompiler.loadClass()
 		Field f = SpelExpression.class.getDeclaredField("compiledAst");
 		Set<Object> classloadersUsed = new HashSet<>();
-		for (int i=0;i<1500;i++) { // 1500 is greater than SpelCompiler.CLASSES_DEFINED_LIMIT
+		for (int i =0; i < 1500; i++) {  // 1500 is greater than SpelCompiler.CLASSES_DEFINED_LIMIT
 			expression = parser.parseExpression("4 + 5");
-			assertEquals(9, (int)expression.getValue(Integer.class));
+			assertEquals(9, (int) expression.getValue(Integer.class));
 			assertCanCompile(expression);
 			f.setAccessible(true);
 			CompiledExpression cEx = (CompiledExpression)f.get(expression);
 			classloadersUsed.add(cEx.getClass().getClassLoader());
-			assertEquals(9, (int)expression.getValue(Integer.class));
+			assertEquals(9, (int) expression.getValue(Integer.class));
 		}
 		assertTrue(classloadersUsed.size() > 1);
 	}
@@ -474,7 +474,7 @@ public class SpelCompilationCoverageTests extends AbstractExpressionTests {
 		expression = parser.parseExpression("T(Integer).valueOf(42)");
 		expression.getValue(Integer.class);
 		assertCanCompile(expression);
-		assertEquals(new Integer(42), expression.getValue(new StandardEvaluationContext(), Integer.class));
+		assertEquals(new Integer(42), expression.getValue(Integer.class));
 
 		// Code gen is different for -1 .. 6 because there are bytecode instructions specifically for those
 		// values
@@ -853,9 +853,9 @@ public class SpelCompilationCoverageTests extends AbstractExpressionTests {
 		assertEquals("4.0", expression.getValue(ctx).toString());
 	}
 
-	// Confirms visibility of what is being called.
 	@Test
 	public void functionReferenceVisibility_SPR12359() throws Exception {
+		// Confirms visibility of what is being called.
 		StandardEvaluationContext context = new StandardEvaluationContext(new Object[] {"1"});
 		context.registerFunction("doCompare", SomeCompareMethod.class.getDeclaredMethod(
 				"compare", Object.class, Object.class));
@@ -866,7 +866,7 @@ public class SpelCompilationCoverageTests extends AbstractExpressionTests {
 		assertCantCompile(expression);
 
 		// type not public but method is
-		context = new StandardEvaluationContext(new  Object[] {"1"});
+		context = new StandardEvaluationContext(new Object[] {"1"});
 		context.registerFunction("doCompare", SomeCompareMethod.class.getDeclaredMethod(
 				"compare2", Object.class, Object.class));
 		context.setVariable("arg", "2");
@@ -877,7 +877,7 @@ public class SpelCompilationCoverageTests extends AbstractExpressionTests {
 
 	@Test
 	public void functionReferenceNonCompilableArguments_SPR12359() throws Exception {
-		StandardEvaluationContext context = new StandardEvaluationContext(new  Object[] {"1"});
+		StandardEvaluationContext context = new StandardEvaluationContext(new Object[] {"1"});
 		context.registerFunction("negate", SomeCompareMethod2.class.getDeclaredMethod(
 				"negate", Integer.TYPE));
 		context.setVariable("arg", "2");
@@ -3093,7 +3093,7 @@ public class SpelCompilationCoverageTests extends AbstractExpressionTests {
 				new SpelParserConfiguration(SpelCompilerMode.IMMEDIATE, getClass().getClassLoader()));
 		Person3 person = new Person3("foo", 1);
 		SpelExpression expression = parser.parseRaw("#it?.age?.equals([0])");
-		StandardEvaluationContext context = new StandardEvaluationContext(new Object[] { 1 });
+		StandardEvaluationContext context = new StandardEvaluationContext(new Object[] {1});
 		context.setVariable("it", person);
 		expression.setEvaluationContext(context);
 		assertTrue(expression.getValue(Boolean.class));
@@ -3120,8 +3120,7 @@ public class SpelCompilationCoverageTests extends AbstractExpressionTests {
 		// code generation for ENGLISH should notice there is something on the stack that
 		// is not required and pop it off.
 		expression = parser.parseExpression("#userId.toString().toLowerCase(T(java.util.Locale).ENGLISH)");
-		StandardEvaluationContext context =
-				new StandardEvaluationContext();
+		StandardEvaluationContext context = new StandardEvaluationContext();
 		context.setVariable("userId", "RoDnEy");
 		assertEquals("rodney", expression.getValue(context));
 		assertCanCompile(expression);
@@ -3270,8 +3269,7 @@ public class SpelCompilationCoverageTests extends AbstractExpressionTests {
 
 		expression = parser.parseExpression("#it?.age.equals([0])");
 		Person person = new Person(1);
-		StandardEvaluationContext context =
-				new StandardEvaluationContext(new Object[] { person.getAge() });
+		StandardEvaluationContext context = new StandardEvaluationContext(new Object[] {person.getAge()});
 		context.setVariable("it", person);
 		assertTrue(expression.getValue(context, Boolean.class));
 		assertCanCompile(expression);
@@ -3279,29 +3277,26 @@ public class SpelCompilationCoverageTests extends AbstractExpressionTests {
 
 		// Variant of above more like what was in the bug report:
 		SpelExpressionParser parser = new SpelExpressionParser(
-				new SpelParserConfiguration(SpelCompilerMode.IMMEDIATE,
-						getClass().getClassLoader()));
+				new SpelParserConfiguration(SpelCompilerMode.IMMEDIATE, getClass().getClassLoader()));
 
 		SpelExpression ex = parser.parseRaw("#it?.age.equals([0])");
-		context = new StandardEvaluationContext(new Object[] { person.getAge() });
+		context = new StandardEvaluationContext(new Object[] {person.getAge()});
 		context.setVariable("it", person);
 		assertTrue(ex.getValue(context, Boolean.class));
 		assertTrue(ex.getValue(context, Boolean.class));
 
 		PersonInOtherPackage person2 = new PersonInOtherPackage(1);
 		ex = parser.parseRaw("#it?.age.equals([0])");
-		context =
-				new StandardEvaluationContext(new Object[] { person2.getAge() });
+		context = new StandardEvaluationContext(new Object[] {person2.getAge()});
 		context.setVariable("it", person2);
 		assertTrue(ex.getValue(context, Boolean.class));
 		assertTrue(ex.getValue(context, Boolean.class));
 
 		ex = parser.parseRaw("#it?.age.equals([0])");
-		context =
-				new StandardEvaluationContext(new Object[] { person2.getAge() });
+		context = new StandardEvaluationContext(new Object[] {person2.getAge()});
 		context.setVariable("it", person2);
-		assertTrue((Boolean)ex.getValue(context));
-		assertTrue((Boolean)ex.getValue(context));
+		assertTrue((Boolean) ex.getValue(context));
+		assertTrue((Boolean) ex.getValue(context));
 	}
 
 	@Test