Update Repackager to use Java 8 APIs safely

Previously, Repackager used Java 8 APIs without protecting against the
possibility of a NoSuchMethodError on earlier versions of Java.
This commit wraps the Java 8 APIs in try-catch blocks to ensure
that they do not cause a failure on Java versions before 8, while
still making full use of Java 8's capabilities when available.

Closes gh-5280

spring-boot-tools/spring-boot-loader-tools/pom.xml

@@ -135,6 +135,7 @@
 					<annotations>
 						<annotation>org.springframework.boot.loader.tools.UsesUnsafeJava</annotation>
 						<annotation>org.springframework.lang.UsesJava7</annotation>
+						<annotation>org.springframework.lang.UsesJava8</annotation>
 					</annotations>
 				</configuration>
 			</plugin>

spring-boot-tools/spring-boot-loader-tools/src/main/java/org/springframework/boot/loader/tools/Repackager.java

@@ -29,6 +29,7 @@ import java.util.jar.JarFile;
 import java.util.jar.Manifest;
 
 import org.springframework.boot.loader.tools.JarWriter.EntryTransformer;
+import org.springframework.lang.UsesJava8;
 
 /**
  * Utility class that can be used to repackage an archive so that it can be executed using
@@ -339,19 +340,49 @@ public class Repackager {
 			}
 			renamedEntry.setCompressedSize(entry.getCompressedSize());
 			renamedEntry.setCrc(entry.getCrc());
-			if (entry.getCreationTime() != null) {
-				renamedEntry.setCreationTime(entry.getCreationTime());
-			}
+			setCreationTimeIfPossible(entry, renamedEntry);
 			if (entry.getExtra() != null) {
 				renamedEntry.setExtra(entry.getExtra());
 			}
-			if (entry.getLastAccessTime() != null) {
-				renamedEntry.setLastAccessTime(entry.getLastAccessTime());
+			setLastAccessTimeIfPossible(entry, renamedEntry);
+			setLastModifiedTimeIfPossible(entry, renamedEntry);
+			return renamedEntry;
+		}
+
+		@UsesJava8
+		private void setCreationTimeIfPossible(JarEntry source, JarEntry target) {
+			try {
+				if (source.getCreationTime() != null) {
+					target.setCreationTime(source.getCreationTime());
+				}
 			}
-			if (entry.getLastModifiedTime() != null) {
-				renamedEntry.setLastModifiedTime(entry.getLastModifiedTime());
+			catch (NoSuchMethodError ex) {
+				// Not running on Java 8. Continue.
+			}
+		}
+
+		@UsesJava8
+		private void setLastAccessTimeIfPossible(JarEntry source, JarEntry target) {
+			try {
+				if (source.getLastAccessTime() != null) {
+					target.setLastAccessTime(source.getLastAccessTime());
+				}
+			}
+			catch (NoSuchMethodError ex) {
+				// Not running on Java 8. Continue.
+			}
+		}
+
+		@UsesJava8
+		private void setLastModifiedTimeIfPossible(JarEntry source, JarEntry target) {
+			try {
+				if (source.getLastModifiedTime() != null) {
+					target.setLastModifiedTime(source.getLastModifiedTime());
+				}
+			}
+			catch (NoSuchMethodError ex) {
+				// Not running on Java 8. Continue.
 			}
-			return renamedEntry;
 		}
 
 	}