1 /* 2 * Copyright (C) 2017 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 import AAA.Derived; 18 19 public class Main { 20 public static void main(String[] args) { 21 try { 22 // Allocate memory for the "AAA.Derived" class name before eating memory. 23 String aaaDerivedName = "AAA.Derived"; 24 System.out.println("Eating all memory."); 25 // Resolve VMClassLoader before eating all the memory since we can not fail 26 // initializtaion of boot classpath classes. 27 Class.forName("java.lang.VMClassLoader"); 28 Object memory = eatAllMemory(); 29 30 // This test assumes that Derived is not yet resolved. In some configurations 31 // (notably interp-ac), Derived is already resolved by verifying Main at run 32 // time. Therefore we cannot assume that we get a certain `value` and need to 33 // simply check for consistency, i.e. `value == another_value`. 34 int value = 0; 35 try { 36 // If the ArtMethod* is erroneously left in the DexCache, this 37 // shall succeed despite the class Derived being unresolved so 38 // far. Otherwise, we shall throw OOME trying to resolve it. 39 value = Derived.foo(); 40 } catch (OutOfMemoryError e) { 41 value = -1; 42 } 43 int another_value = 0; 44 try { 45 // For comparison, try to resolve the class Derived directly. 46 Class.forName(aaaDerivedName, false, Main.class.getClassLoader()); 47 another_value = 42; 48 } catch (OutOfMemoryError e) { 49 another_value = -1; 50 } 51 boolean memoryWasAllocated = (memory != null); 52 memory = null; 53 System.out.println("memoryWasAllocated = " + memoryWasAllocated); 54 System.out.println("match: " + (value == another_value)); 55 if (value != another_value || (value != -1 && value != 42)) { 56 // Mismatch or unexpected value, print additional debugging information. 57 System.out.println("value: " + value); 58 System.out.println("another_value: " + another_value); 59 } 60 } catch (Throwable t) { 61 t.printStackTrace(System.out); 62 } 63 } 64 65 public static Object eatAllMemory() { 66 Object[] result = null; 67 int size = 1000000; 68 while (result == null && size != 0) { 69 try { 70 result = new Object[size]; 71 } catch (OutOfMemoryError oome) { 72 size /= 2; 73 } 74 } 75 if (result != null) { 76 int index = 0; 77 while (index != result.length && size != 0) { 78 try { 79 result[index] = new byte[size]; 80 ++index; 81 } catch (OutOfMemoryError oome) { 82 size /= 2; 83 } 84 } 85 } 86 return result; 87 } 88 } 89
