clean up some error throwing code

Author: gavinking

hibernate-core/src/main/java/org/hibernate/boot/registry/classloading/internal/AggregatedClassLoader.java

@@ -10,7 +10,6 @@
 import java.util.Iterator;
 import java.util.LinkedHashSet;
 
-import org.hibernate.internal.util.ExceptionHelper;
 
 public class AggregatedClassLoader extends ClassLoader {
 	private final ClassLoader[] individualClassLoaders;
@@ -122,7 +121,7 @@ else if ( !sysCLReturned && systemClassLoader != null ) {
 
 	private Iterator<ClassLoader> newTcclNeverIterator() {
 		final ClassLoader systemClassLoader = locateSystemClassLoader();
-		return new Iterator<ClassLoader>() {
+		return new Iterator<>() {
 			private int currentIndex = 0;
 			private boolean sysCLReturned = false;
 
@@ -182,7 +181,7 @@ public URL nextElement() {
 
 	@Override
 	protected URL findResource(String name) {
-		final Iterator<ClassLoader> clIterator = newClassLoaderIterator();
+		final var clIterator = newClassLoaderIterator();
 		while ( clIterator.hasNext() ) {
 			final ClassLoader classLoader = clIterator.next();
 			final URL resource = classLoader.getResource( name );
@@ -195,22 +194,18 @@ protected URL findResource(String name) {
 
 	@Override
 	protected Class<?> findClass(String name) throws ClassNotFoundException {
-		final Iterator<ClassLoader> clIterator = newClassLoaderIterator();
-		Throwable t = null;
+		final var clIterator = newClassLoaderIterator();
+		final var exception = new ClassNotFoundException( "Could not load requested class: " + name );
 		while ( clIterator.hasNext() ) {
 			final ClassLoader classLoader = clIterator.next();
 			try {
 				return classLoader.loadClass( name );
 			}
-			catch (Exception ex) {
-				ExceptionHelper.combine( ( t == null ? t = new Throwable() : t ), ex );
-			}
-			catch (LinkageError le) {
-				ExceptionHelper.combine( ( t == null ? t = new Throwable() : t ), le );
+			catch (Exception|LinkageError ex) {
+				exception.addSuppressed( ex );
 			}
 		}
-
-		throw new ClassNotFoundException( "Could not load requested class : " + name, ( t != null && t.getSuppressed().length > 0 ? t : null ) );
+		throw exception;
 	}
 
 	private static ClassLoader locateSystemClassLoader() {

hibernate-core/src/main/java/org/hibernate/internal/SessionImpl.java

@@ -721,7 +721,7 @@ private void firePersist(final PersistEvent event) {
 			}
 		}
 		if ( originalException != null ) {
-			ExceptionHelper.doThrow( originalException );
+			ExceptionHelper.rethrow( originalException );
 		}
 	}
 

hibernate-core/src/main/java/org/hibernate/internal/util/ExceptionHelper.java

@@ -11,37 +11,28 @@ private ExceptionHelper() {
 	}
 
 	/**
-	 * Throws the given throwable even if it is a checked exception.
+	 * Throws the given {@link Throwable}, even if it's a checked exception.
 	 *
-	 * @param e The throwable to throw.
+	 * @param throwable The {@code Throwable} to throw.
 	 */
-	public static void doThrow(Throwable e) {
-		ExceptionHelper.doThrow0(e);
+	public static void rethrow(Throwable throwable) {
+		sneakyThrow( throwable );
 	}
 
-	public static Throwable getRootCause(Throwable error) {
-		Throwable toProcess = error;
-		while ( toProcess.getCause() != null ) {
-			toProcess = toProcess.getCause();
-		}
-		return toProcess;
+	@SuppressWarnings("unchecked")
+	private static <T extends Throwable> void sneakyThrow(Throwable e)
+			throws T {
+		throw (T) e;
 	}
 
-	public static <T extends Throwable> T combine(T throwable, T otherThrowable) {
-		T toThrow = throwable;
-		if ( otherThrowable != null ) {
-			if ( toThrow != null ) {
-				toThrow.addSuppressed( otherThrowable );
-			}
-			else {
-				toThrow = otherThrowable;
+	public static Throwable getRootCause(Throwable error) {
+		var next = error;
+		while ( true ) {
+			final var current = next;
+			next = current.getCause();
+			if ( next == null ) {
+				return current;
 			}
 		}
-		return toThrow;
-	}
-
-	@SuppressWarnings("unchecked")
-	private static <T extends Throwable> void doThrow0(Throwable e) throws T {
-		throw (T) e;
 	}
 }

hibernate-core/src/main/java/org/hibernate/resource/transaction/backend/jdbc/internal/DdlTransactionIsolatorNonJtaImpl.java

@@ -122,7 +122,7 @@ public void release() {
 				}
 			}
 			if ( originalException != null ) {
-				ExceptionHelper.doThrow( originalException );
+				ExceptionHelper.rethrow( originalException );
 			}
 		}
 	}