8312489: Increase jdk.jar.maxSignatureFileSize default which is too low for JARs such as WhiteSource/Mend unified agent jar

Backport-of: e47a84f23dd2608c6f5748093eefe301fb5bf750

Author: gnu-andrew

src/java.base/share/classes/java/util/jar/JarFile.java

@@ -809,7 +809,9 @@ private byte[] getBytes(ZipEntry ze) throws IOException {
                 throw new IOException("Unsupported size: " + uncompressedSize +
                         " for JarEntry " + ze.getName() +
                         ". Allowed max size: " +
-                        SignatureFileVerifier.MAX_SIG_FILE_SIZE + " bytes");
+                        SignatureFileVerifier.MAX_SIG_FILE_SIZE + " bytes. " +
+                        "You can use the jdk.jar.maxSignatureFileSize " +
+                        "system property to increase the default value.");
             }
             int len = (int)uncompressedSize;
             int bytesRead;

src/java.base/share/classes/sun/security/util/SignatureFileVerifier.java

@@ -852,16 +852,16 @@ private static int initializeMaxSigFileSize() {
          * the maximum allowed number of bytes for the signature-related files
          * in a JAR file.
          */
-        Integer tmp = GetIntegerAction.privilegedGetProperty(
-                "jdk.jar.maxSignatureFileSize", 8000000);
+        int tmp = GetIntegerAction.privilegedGetProperty(
+                "jdk.jar.maxSignatureFileSize", 16000000);
         if (tmp < 0 || tmp > MAX_ARRAY_SIZE) {
             if (debug != null) {
-                debug.println("Default signature file size 8000000 bytes " +
-                        "is used as the specified size for the " +
-                        "jdk.jar.maxSignatureFileSize system property " +
+                debug.println("The default signature file size of 16000000 bytes " +
+                        "will be used for the jdk.jar.maxSignatureFileSize " +
+                        "system property since the specified value " +
                         "is out of range: " + tmp);
             }
-            tmp = 8000000;
+            tmp = 16000000;
         }
         return tmp;
     }