diff --git a/spring-context/src/main/java/org/springframework/context/annotation/ConfigurationClassParser.java b/spring-context/src/main/java/org/springframework/context/annotation/ConfigurationClassParser.java
index 0d5221d58fb..bf188510d9f 100644
--- a/spring-context/src/main/java/org/springframework/context/annotation/ConfigurationClassParser.java
+++ b/spring-context/src/main/java/org/springframework/context/annotation/ConfigurationClassParser.java
@@ -66,6 +66,7 @@ import org.springframework.core.type.StandardAnnotationMetadata;
 import org.springframework.core.type.classreading.MetadataReader;
 import org.springframework.core.type.classreading.MetadataReaderFactory;
 import org.springframework.core.type.filter.AssignableTypeFilter;
+import org.springframework.util.Assert;
 import org.springframework.util.LinkedMultiValueMap;
 import org.springframework.util.MultiValueMap;
 import org.springframework.util.StringUtils;
@@ -315,9 +316,7 @@ class ConfigurationClassParser {
 		String name = propertySource.getString("name");
 		String[] locations = propertySource.getStringArray("value");
 		boolean ignoreResourceNotFound = propertySource.getBoolean("ignoreResourceNotFound");
-		if (locations.length == 0) {
-			throw new IllegalArgumentException("At least one @PropertySource(value) location is required");
-		}
+		Assert.isTrue(locations.length > 0, "At least one @PropertySource(value) location is required");
 		for (String location : locations) {
 			try {
 				String resolvedLocation = this.environment.resolveRequiredPlaceholders(location);
@@ -401,6 +400,7 @@ class ConfigurationClassParser {
 		if (importCandidates.isEmpty()) {
 			return;
 		}
+
 		if (checkForCircularImports && this.importStack.contains(configClass)) {
 			this.problemReporter.error(new CircularImportProblem(configClass, this.importStack, configClass.getMetadata()));
 		}
@@ -409,12 +409,13 @@ class ConfigurationClassParser {
 			try {
 				for (SourceClass candidate : importCandidates) {
 					if (candidate.isAssignable(ImportSelector.class)) {
-						// the candidate class is an ImportSelector -> delegate to it to determine imports
+						// Candidate class is an ImportSelector -> delegate to it to determine imports
 						Class<?> candidateClass = candidate.loadClass();
 						ImportSelector selector = BeanUtils.instantiateClass(candidateClass, ImportSelector.class);
 						invokeAwareMethods(selector);
 						if (selector instanceof DeferredImportSelector) {
-							this.deferredImportSelectors.add(new DeferredImportSelectorHolder(configClass, (DeferredImportSelector) selector));
+							this.deferredImportSelectors.add(
+									new DeferredImportSelectorHolder(configClass, (DeferredImportSelector) selector));
 						}
 						else {
 							String[] importClassNames = selector.selectImports(currentSourceClass.getMetadata());
@@ -423,15 +424,19 @@ class ConfigurationClassParser {
 						}
 					}
 					else if (candidate.isAssignable(ImportBeanDefinitionRegistrar.class)) {
-						// the candidate class is an ImportBeanDefinitionRegistrar -> delegate to it to register additional bean definitions
+						// Candidate class is an ImportBeanDefinitionRegistrar ->
+						// delegate to it to register additional bean definitions
 						Class<?> candidateClass = candidate.loadClass();
-						ImportBeanDefinitionRegistrar registrar = BeanUtils.instantiateClass(candidateClass, ImportBeanDefinitionRegistrar.class);
+						ImportBeanDefinitionRegistrar registrar =
+								BeanUtils.instantiateClass(candidateClass, ImportBeanDefinitionRegistrar.class);
 						invokeAwareMethods(registrar);
 						configClass.addImportBeanDefinitionRegistrar(registrar, currentSourceClass.getMetadata());
 					}
 					else {
-						// candidate class not an ImportSelector or ImportBeanDefinitionRegistrar -> process it as a @Configuration class
-						this.importStack.registerImport(currentSourceClass.getMetadata(), candidate.getMetadata().getClassName());
+						// Candidate class not an ImportSelector or ImportBeanDefinitionRegistrar ->
+						// process it as a @Configuration class
+						this.importStack.registerImport(
+								currentSourceClass.getMetadata(), candidate.getMetadata().getClassName());
 						processConfigurationClass(candidate.asConfigClass(configClass));
 					}
 				}
@@ -645,12 +650,12 @@ class ConfigurationClassParser {
 
 
 	/**
-	 * Simple wrapper that allows annotated source classes to be dealt with in a uniform
-	 * manor, regardless of how they are loaded.
+	 * Simple wrapper that allows annotated source classes to be dealt with
+	 * in a uniform manner, regardless of how they are loaded.
 	 */
 	private class SourceClass {
 
-		private final Object source; // Class or MetaDataReader
+		private final Object source;  // Class or MetadataReader
 
 		private final AnnotationMetadata metadata;
 
diff --git a/spring-context/src/test/java/org/springframework/context/annotation/spr12334/Spr12334Tests.java b/spring-context/src/test/java/org/springframework/context/annotation/spr12334/Spr12334Tests.java
index 56e7a3d8b27..c98fc077382 100644
--- a/spring-context/src/test/java/org/springframework/context/annotation/spr12334/Spr12334Tests.java
+++ b/spring-context/src/test/java/org/springframework/context/annotation/spr12334/Spr12334Tests.java
@@ -33,6 +33,8 @@ public class Spr12334Tests {
 
 	@Test
 	public void shouldNotScanTwice() {
+		TestImport.scanned = false;
+
 		AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext();
 		context.scan(TestImport.class.getPackage().getName());
 		context.refresh();
@@ -53,14 +55,14 @@ public class Spr12334Tests {
 
 	public static class TestImport implements ImportBeanDefinitionRegistrar {
 
-		private boolean scanned = false;
+		private static boolean scanned = false;
 
 		@Override
 		public void registerBeanDefinitions(AnnotationMetadata metadata, BeanDefinitionRegistry registry)  {
-			if (this.scanned) {
+			if (scanned) {
 				throw new IllegalStateException("Already scanned");
 			}
-			this.scanned = true;
+			scanned = true;
 		}
 	}