--- old/src/java.base/share/classes/com/sun/crypto/provider/DHParameterGenerator.java	Wed Mar 23 16:12:12 2016
+++ new/src/java.base/share/classes/com/sun/crypto/provider/DHParameterGenerator.java	Wed Mar 23 16:12:12 2016
@@ -25,6 +25,7 @@
 
 package com.sun.crypto.provider;
 
+import java.math.BigInteger;
 import java.security.*;
 import java.security.spec.*;
 import javax.crypto.spec.DHParameterSpec;
@@ -46,8 +47,7 @@
  * @see java.security.spec.AlgorithmParameterSpec
  * @see DHParameters
  */
-public final class DHParameterGenerator
-extends AlgorithmParameterGeneratorSpi {
+public final class DHParameterGenerator extends AlgorithmParameterGeneratorSpi {
 
     // The size in bits of the prime modulus
     private int primeSize = 2048;
@@ -59,12 +59,15 @@
     private SecureRandom random = null;
 
     private static void checkKeySize(int keysize)
-        throws InvalidAlgorithmParameterException {
-        if ((keysize != 2048) &&
-            ((keysize < 512) || (keysize > 1024) || (keysize % 64 != 0))) {
-            throw new InvalidAlgorithmParameterException(
-                "Keysize must be multiple of 64 ranging from "
-                + "512 to 1024 (inclusive), or 2048");
+            throws InvalidParameterException {
+
+        boolean supported = ((keysize == 2048) || (keysize == 3072) ||
+            ((keysize >= 512) && (keysize <= 1024) && (keysize % 64 == 0)));
+
+        if (!supported) {
+            throw new InvalidParameterException
+                ("Keysize must be multiple of 64 and range "
+                 + "from 512 to 1024 (inclusive), or 2048, 3072");
         }
     }
 
@@ -76,13 +79,9 @@
      * @param keysize the keysize (size of prime modulus) in bits
      * @param random the source of randomness
      */
+    @Override
     protected void engineInit(int keysize, SecureRandom random) {
-        // Re-uses DSA parameters and thus have the same range
-        try {
-            checkKeySize(keysize);
-        } catch (InvalidAlgorithmParameterException ex) {
-            throw new InvalidParameterException(ex.getMessage());
-        }
+        checkKeySize(keysize);
         this.primeSize = keysize;
         this.random = random;
     }
@@ -98,9 +97,10 @@
      * @exception InvalidAlgorithmParameterException if the given parameter
      * generation values are inappropriate for this parameter generator
      */
+    @Override
     protected void engineInit(AlgorithmParameterSpec genParamSpec,
-                              SecureRandom random)
-        throws InvalidAlgorithmParameterException {
+            SecureRandom random) throws InvalidAlgorithmParameterException {
+
         if (!(genParamSpec instanceof DHGenParameterSpec)) {
             throw new InvalidAlgorithmParameterException
                 ("Inappropriate parameter type");
@@ -107,23 +107,19 @@
         }
 
         DHGenParameterSpec dhParamSpec = (DHGenParameterSpec)genParamSpec;
-
         primeSize = dhParamSpec.getPrimeSize();
-
-        // Re-uses DSA parameters and thus have the same range
-        checkKeySize(primeSize);
-
         exponentSize = dhParamSpec.getExponentSize();
-        if (exponentSize <= 0) {
-            throw new InvalidAlgorithmParameterException
-                ("Exponent size must be greater than zero");
+        if ((exponentSize <= 0) || (exponentSize >= primeSize)) {
+            throw new InvalidAlgorithmParameterException(
+                "Exponent size must be positive and less than modulus size");
         }
-
-        // Require exponentSize < primeSize
-        if (exponentSize >= primeSize) {
-            throw new InvalidAlgorithmParameterException
-                ("Exponent size must be less than modulus size");
+        try {
+            checkKeySize(primeSize);
+        } catch (InvalidParameterException ipe) {
+            throw new InvalidAlgorithmParameterException(ipe.getMessage());
         }
+
+        this.random = random;
     }
 
     /**
@@ -131,25 +127,23 @@
      *
      * @return the new AlgorithmParameters object
      */
+    @Override
     protected AlgorithmParameters engineGenerateParameters() {
-        AlgorithmParameters algParams = null;
 
-        if (this.exponentSize == 0) {
-            this.exponentSize = this.primeSize - 1;
+        if (random == null) {
+            random = SunJCE.getRandom();
         }
 
-        if (this.random == null)
-            this.random = SunJCE.getRandom();
-
+        BigInteger paramP = null;
+        BigInteger paramG = null;
         try {
-            AlgorithmParameterGenerator paramGen;
-            DSAParameterSpec dsaParamSpec;
+            AlgorithmParameterGenerator dsaParamGen =
+                    AlgorithmParameterGenerator.getInstance("DSA");
+            dsaParamGen.init(primeSize, random);
+            AlgorithmParameters dsaParams = dsaParamGen.generateParameters();
+            DSAParameterSpec dsaParamSpec =
+                    dsaParams.getParameterSpec(DSAParameterSpec.class);
 
-            paramGen = AlgorithmParameterGenerator.getInstance("DSA");
-            paramGen.init(this.primeSize, random);
-            algParams = paramGen.generateParameters();
-            dsaParamSpec = algParams.getParameterSpec(DSAParameterSpec.class);
-
             DHParameterSpec dhParamSpec;
             if (this.exponentSize > 0) {
                 dhParamSpec = new DHParameterSpec(dsaParamSpec.getP(),
@@ -159,16 +153,13 @@
                 dhParamSpec = new DHParameterSpec(dsaParamSpec.getP(),
                                                   dsaParamSpec.getG());
             }
-            algParams = AlgorithmParameters.getInstance("DH",
-                    SunJCE.getInstance());
+            AlgorithmParameters algParams =
+                    AlgorithmParameters.getInstance("DH", SunJCE.getInstance());
             algParams.init(dhParamSpec);
-        } catch (InvalidParameterSpecException e) {
-            // this should never happen
-            throw new RuntimeException(e.getMessage());
-        } catch (NoSuchAlgorithmException e) {
-            // this should never happen, because we provide it
-            throw new RuntimeException(e.getMessage());
+
+            return algParams;
+        } catch (Exception ex) {
+            throw new ProviderException("Unexpected exception: " + ex);
         }
-        return algParams;
     }
 }