ClassPathResource uses specific constructors in createRelative

Issue: SPR-16146

(cherry picked from commit d00e4f1)

Author: jhoeller

spring-core/src/main/java/org/springframework/core/io/ClassPathResource.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2015 the original author or authors.
+ * Copyright 2002-2017 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -197,7 +197,8 @@ public URL getURL() throws IOException {
 	@Override
 	public Resource createRelative(String relativePath) {
 		String pathToUse = StringUtils.applyRelativePath(this.path, relativePath);
-		return new ClassPathResource(pathToUse, this.classLoader, this.clazz);
+		return (this.clazz != null ? new ClassPathResource(pathToUse, this.clazz) :
+				new ClassPathResource(pathToUse, this.classLoader));
 	}
 
 	/**

spring-core/src/test/java/org/springframework/core/io/ClassPathResourceTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2012 the original author or authors.
+ * Copyright 2002-2017 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -47,40 +47,19 @@ public class ClassPathResourceTests {
 	private static final Pattern DESCRIPTION_PATTERN = Pattern.compile("^class path resource \\[(.+?)\\]$");
 
 
-	private void assertDescriptionContainsExpectedPath(ClassPathResource resource, String expectedPath) {
-		Matcher matcher = DESCRIPTION_PATTERN.matcher(resource.getDescription());
-		assertTrue(matcher.matches());
-		assertEquals(1, matcher.groupCount());
-		String match = matcher.group(1);
-
-		assertEquals(expectedPath, match);
-	}
-
-	private void assertExceptionContainsFullyQualifiedPath(ClassPathResource resource) {
-		try {
-			resource.getInputStream();
-			fail("FileNotFoundException expected for resource: " + resource);
-		}
-		catch (IOException ex) {
-			assertThat(ex, instanceOf(FileNotFoundException.class));
-			assertThat(ex.getMessage(), containsString(FQ_RESOURCE_PATH));
-		}
-	}
-
 	@Test
 	public void stringConstructorRaisesExceptionWithFullyQualifiedPath() {
 		assertExceptionContainsFullyQualifiedPath(new ClassPathResource(FQ_RESOURCE_PATH));
 	}
 
 	@Test
 	public void classLiteralConstructorRaisesExceptionWithFullyQualifiedPath() {
-		assertExceptionContainsFullyQualifiedPath(new ClassPathResource(NONEXISTENT_RESOURCE_NAME, this.getClass()));
+		assertExceptionContainsFullyQualifiedPath(new ClassPathResource(NONEXISTENT_RESOURCE_NAME, getClass()));
 	}
 
 	@Test
 	public void classLoaderConstructorRaisesExceptionWithFullyQualifiedPath() {
-		assertExceptionContainsFullyQualifiedPath(new ClassPathResource(FQ_RESOURCE_PATH,
-			this.getClass().getClassLoader()));
+		assertExceptionContainsFullyQualifiedPath(new ClassPathResource(FQ_RESOURCE_PATH, getClass().getClassLoader()));
 	}
 
 	@Test
@@ -91,31 +70,64 @@ public void getDescriptionWithStringConstructor() {
 	@Test
 	public void getDescriptionWithStringConstructorAndLeadingSlash() {
 		assertDescriptionContainsExpectedPath(new ClassPathResource(FQ_RESOURCE_PATH_WITH_LEADING_SLASH),
-			FQ_RESOURCE_PATH);
+				FQ_RESOURCE_PATH);
 	}
 
 	@Test
 	public void getDescriptionWithClassLiteralConstructor() {
-		assertDescriptionContainsExpectedPath(new ClassPathResource(NONEXISTENT_RESOURCE_NAME, this.getClass()),
-			FQ_RESOURCE_PATH);
+		assertDescriptionContainsExpectedPath(new ClassPathResource(NONEXISTENT_RESOURCE_NAME, getClass()),
+				FQ_RESOURCE_PATH);
 	}
 
 	@Test
 	public void getDescriptionWithClassLiteralConstructorAndLeadingSlash() {
 		assertDescriptionContainsExpectedPath(
-			new ClassPathResource(FQ_RESOURCE_PATH_WITH_LEADING_SLASH, this.getClass()), FQ_RESOURCE_PATH);
+				new ClassPathResource(FQ_RESOURCE_PATH_WITH_LEADING_SLASH, getClass()), FQ_RESOURCE_PATH);
 	}
 
 	@Test
 	public void getDescriptionWithClassLoaderConstructor() {
 		assertDescriptionContainsExpectedPath(
-			new ClassPathResource(FQ_RESOURCE_PATH, this.getClass().getClassLoader()), FQ_RESOURCE_PATH);
+				new ClassPathResource(FQ_RESOURCE_PATH, getClass().getClassLoader()), FQ_RESOURCE_PATH);
 	}
 
 	@Test
 	public void getDescriptionWithClassLoaderConstructorAndLeadingSlash() {
-		assertDescriptionContainsExpectedPath(new ClassPathResource(FQ_RESOURCE_PATH_WITH_LEADING_SLASH,
-			this.getClass().getClassLoader()), FQ_RESOURCE_PATH);
+		assertDescriptionContainsExpectedPath(
+				new ClassPathResource(FQ_RESOURCE_PATH_WITH_LEADING_SLASH, getClass().getClassLoader()), FQ_RESOURCE_PATH);
+	}
+
+	@Test
+	public void dropLeadingSlashForClassLoaderAccess() {
+		assertEquals("test.html", new ClassPathResource("/test.html").getPath());
+		assertEquals("test.html", ((ClassPathResource) new ClassPathResource("").createRelative("/test.html")).getPath());
+	}
+
+	@Test
+	public void preserveLeadingSlashForClassRelativeAccess() {
+		assertEquals("/test.html", new ClassPathResource("/test.html", getClass()).getPath());
+		assertEquals("/test.html", ((ClassPathResource) new ClassPathResource("", getClass()).createRelative("/test.html")).getPath());
+	}
+
+
+	private void assertDescriptionContainsExpectedPath(ClassPathResource resource, String expectedPath) {
+		Matcher matcher = DESCRIPTION_PATTERN.matcher(resource.getDescription());
+		assertTrue(matcher.matches());
+		assertEquals(1, matcher.groupCount());
+		String match = matcher.group(1);
+
+		assertEquals(expectedPath, match);
+	}
+
+	private void assertExceptionContainsFullyQualifiedPath(ClassPathResource resource) {
+		try {
+			resource.getInputStream();
+			fail("FileNotFoundException expected for resource: " + resource);
+		}
+		catch (IOException ex) {
+			assertThat(ex, instanceOf(FileNotFoundException.class));
+			assertThat(ex.getMessage(), containsString(FQ_RESOURCE_PATH));
+		}
 	}
 
 }