1 /* 2 * Copyright (c) 2003, Oracle and/or its affiliates. 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 */ 23 24 /* @test 25 * @bug 4806007 26 * @summary Checks for vague exceptions from writeUTF/readUTF 27 * @key randomness 28 */ 29 30 import java.io.*; 31 import java.util.*; 32 33 public class ReadUTF { 34 35 private static Random generator = new Random(); 36 37 private static final int TEST_ITERATIONS = 1000; 38 39 private static final int A_NUMBER_NEAR_65535 = 60000; 40 41 private static final int MAX_CORRUPTIONS_PER_CYCLE = 3; 42 43 public static final void main(String[] args) throws Exception { 44 for (int i=0; i<TEST_ITERATIONS; i++) { 45 try { 46 writeAndReadAString(); 47 } catch (UTFDataFormatException utfdfe) { 48 if (utfdfe.getMessage() == null) 49 throw new RuntimeException("vague exception thrown"); 50 } catch (EOFException eofe) { 51 // These are rare and beyond the scope of the test 52 } 53 } 54 } 55 56 private static void writeAndReadAString() throws Exception { 57 // Write out a string whose UTF-8 encoding is quite possibly 58 // longer than 65535 bytes 59 int length = generator.nextInt(A_NUMBER_NEAR_65535) + 1; 60 ByteArrayOutputStream baos = new ByteArrayOutputStream(); 61 StringBuffer testBuffer = new StringBuffer(); 62 for (int i=0; i<length; i++) 63 testBuffer.append((char)generator.nextInt()); 64 String testString = testBuffer.toString(); 65 DataOutputStream dos = new DataOutputStream(baos); 66 dos.writeUTF(testString); 67 68 // Corrupt the data to produce malformed characters 69 byte[] testBytes = baos.toByteArray(); 70 int dataLength = testBytes.length; 71 int corruptions = generator.nextInt(MAX_CORRUPTIONS_PER_CYCLE); 72 for (int i=0; i<corruptions; i++) { 73 int index = generator.nextInt(dataLength); 74 testBytes[index] = (byte)generator.nextInt(); 75 } 76 77 // Pay special attention to mangling the end to produce 78 // partial characters at end 79 testBytes[dataLength-1] = (byte)generator.nextInt(); 80 testBytes[dataLength-2] = (byte)generator.nextInt(); 81 82 // Attempt to decode the bytes back into a String 83 ByteArrayInputStream bais = new ByteArrayInputStream(testBytes); 84 DataInputStream dis = new DataInputStream(bais); 85 dis.readUTF(); 86 } 87 }