1 /* 2 * Copyright 1998 Sun Microsystems, Inc. All Rights Reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, 20 * CA 95054 USA or visit www.sun.com if you need additional information or 21 * have any questions. 22 */ 23 24 /* @test 25 @bug 4098742 26 @summary Test biginteger modpow method 27 @author Michael McCloskey 28 @run main/othervm ModPowPowersof2 29 */ 30 31 import java.math.BigInteger; 32 import java.io.BufferedReader; 33 import java.io.InputStreamReader; 34 import java.io.File; 35 import java.io.IOException; 36 37 /** 38 * This class tests to see if using modPow on a power 39 * of two crashes the vm 40 * 41 */ 42 public class ModPowPowersof2 { 43 44 public static void main(String args[]) throws Exception { 45 // Construct a command that runs the test in other vm 46 String[] command = new String[4]; 47 int n = 0; 48 49 command[n++] = System.getProperty("java.home") + File.separator + 50 "bin" + File.separator + "java"; 51 if (System.getProperty("java.class.path") != null) { 52 command[n++] = "-classpath"; 53 command[n++] = System.getProperty("java.class.path"); 54 } 55 56 command[n++] = "ModPowPowersof2$ModTester"; 57 58 // Exec another vm to run test in 59 Process p = null; 60 p = Runtime.getRuntime().exec(command); 61 62 // Read the result to determine if test failed 63 BufferedReader in = new BufferedReader(new InputStreamReader( 64 p.getInputStream())); 65 String s; 66 s = in.readLine(); 67 if (s == null) 68 throw new RuntimeException("ModPow causes vm crash"); 69 70 } 71 72 public static class ModTester { 73 public static void main(String [] args) { 74 BigInteger two = BigInteger.valueOf(2); 75 BigInteger four = BigInteger.valueOf(4); 76 77 two.modPow(two, BigInteger.valueOf(4)); 78 two.modPow(two, BigInteger.valueOf(8)); 79 two.modPow(four, BigInteger.valueOf(8)); 80 81 System.out.println("success"); 82 } 83 } 84 85 }