8256919: BCEL: Utility.encode forget to close

Reviewed-by: lancea, bpb, naoto

src/java.xml/share/classes/com/sun/org/apache/bcel/internal/classfile/Utility.java

@@ -42,7 +42,7 @@
 /**
  * Utility functions that do not really belong to any class in particular.
  *
- * @LastModified: May 2021
+ * @LastModified: June 2021
  */
 // @since 6.0 methods are no longer final
 public abstract class Utility {
@@ -1461,6 +1461,7 @@ public static String encode(byte[] bytes, final boolean compress) throws IOExcep
             try (ByteArrayOutputStream baos = new ByteArrayOutputStream();
                     GZIPOutputStream gos = new GZIPOutputStream(baos)) {
                 gos.write(bytes, 0, bytes.length);
+                gos.finish();
                 bytes = baos.toByteArray();
             }
         }

test/jaxp/javax/xml/jaxp/unittest/bcel/UtilityTest.java

@@ -0,0 +1,71 @@
+/*
+ * Copyright (c) 2021, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+package bcel;
+
+import com.sun.org.apache.bcel.internal.classfile.Utility;
+import java.util.Base64;
+import org.testng.annotations.Test;
+
+/*
+ * @test
+ * @bug 8256919
+ * @modules java.xml/com.sun.org.apache.bcel.internal.classfile
+ * @run testng bcel.UtilityTest
+ * @summary Tests the Utility.
+ */
+public class UtilityTest {
+
+    /*
+     * @bug 8256919
+     * Verifies the encode method.
+     */
+    @Test
+    public void test() throws Exception {
+        /**
+         * public class Hello {
+         *     public void hello(){
+         *         System.out.println("Hello,world");
+         *     }
+         *     public static void main(String[] args) {
+         *         Hello hello = new Hello();
+         *         hello.hello();
+         *     }
+         * }
+         * javac Hello.java
+         * cat Hello.class |base64
+         */
+        String bytecodeBase64 = "cHVibGljIGNsYXNzIEhlbGxvIHsKICAgIHB1YmxpYyB2b2lkIGhlbGxvKCl7CiAgICAgICAgU3lzdGVtLm91dC5wcmludGxuKCJIZWxsbyx3b3JsZCIpOwogICAgfQogICAgcHVibGljIHN0YXRpYyB2b2lkIG1haW4oU3RyaW5nW10gYXJncykgewogICAgICAgIEhlbGxvIGhlbGxvID0gbmV3IEhlbGxvKCk7CiAgICAgICAgaGVsbG8uaGVsbG8oKTsKICAgIH0KfQo=";
+        byte[] bytecode = Base64.getDecoder().decode(bytecodeBase64);
+        // encode regression:
+        //(jdk1.8.0_171)$l$8b$I$A$A$A$A$A$A$AM$8e$c1$O$c2$m$QD$ef$7c$c5$a6$tH$M$3f$60$bc$7b$ef$d1x$c0$96$b4$q$5b$m$ec$d6$c6$Y$fe$dd$C$g$3b$c7$99$9d$b7$T$d7$H$ba$B$G4Dp$b5$88$B$de$Cv$c5$W$3c$83$ha$$$beT$z$u$ea_$c4v$d1ae$j$93$f3$8c$5ev$b5$7c$daB$c2$b1S$e7z$9a$8f$qb$c3$3f$e0b$9c$97$3d$ef$d5$e9v$H$93$sR$f0$a7$b7$Z$f5$v$5c$c0$db$ad9$f2K$z$aa$a1$9e$8fv$WY$7c$A$93C$7bZ$ce$A$A$A
+        //(jdk1.8.0_251)$l$8b$I$A$A$A$A$A$A$A
+        String classname = Utility.encode(bytecode,true);
+        /* attempting to decode would result in an exception:
+         *     java.io.EOFException: Unexpected end of ZLIB input stream
+         *if encode is not done properly
+         */
+        Utility.decode(classname, true);
+    }
+
+}