Merge pull request #15465 from dreis2211

* pr/15465:
  Polish "Fix StringSequence.equals() for different lengths"
  Fix StringSequence.equals() for different lengths

spring-boot-project/spring-boot-tools/spring-boot-loader/src/main/java/org/springframework/boot/loader/jar/StringSequence.java

@@ -111,20 +111,20 @@ final class StringSequence implements CharSequence {
 		if (this == obj) {
 			return true;
 		}
-		if (obj == null || !CharSequence.class.isInstance(obj)) {
+		if (!(obj instanceof CharSequence)) {
 			return false;
 		}
 		CharSequence other = (CharSequence) obj;
 		int n = length();
-		if (n == other.length()) {
-			int i = 0;
-			while (n-- != 0) {
-				if (charAt(i) != other.charAt(i)) {
-					return false;
-				}
-				i++;
+		if (n != other.length()) {
+			return false;
+		}
+		int i = 0;
+		while (n-- != 0) {
+			if (charAt(i) != other.charAt(i)) {
+				return false;
 			}
-			return true;
+			i++;
 		}
 		return true;
 	}

spring-boot-project/spring-boot-tools/spring-boot-loader/src/test/java/org/springframework/boot/loader/jar/StringSequenceTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2017 the original author or authors.
+ * Copyright 2012-2018 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.
@@ -167,6 +167,13 @@ public class StringSequenceTests {
 		assertThat(a).isEqualTo(b).isNotEqualTo(c);
 	}
 
+	@Test
+	public void notEqualsWhenSequencesOfDifferentLength() {
+		StringSequence a = new StringSequence("abcd");
+		StringSequence b = new StringSequence("ef");
+		assertThat(a).isNotEqualTo(b);
+	}
+
 	@Test
 	public void startsWithWhenExactMatch() {
 		assertThat(new StringSequence("abc").startsWith("abc")).isTrue();