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      1 /*
      2  * Copyright (C) 2008 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 java.util.Arrays;
     18 import java.util.LinkedList;
     19 
     20 /**
     21  * Exercise the construction and throwing of OutOfMemoryError.
     22  */
     23 public class Main {
     24     public static void main(String args[]) {
     25         System.out.println("tests beginning");
     26         testHugeArray();
     27         testOomeLarge();
     28         testOomeSmall();
     29         System.out.println("tests succeeded");
     30     }
     31 
     32     private static void testHugeArray() {
     33         try {
     34             final int COUNT = 32768*32768 + 4;
     35             int[] tooBig = new int[COUNT];
     36 
     37             Arrays.fill(tooBig, 0xdd);
     38         } catch (OutOfMemoryError oom) {
     39             System.out.println("Got expected huge-array OOM");
     40         }
     41     }
     42 
     43     private static void testOomeLarge() {
     44         System.out.println("testOomeLarge beginning");
     45 
     46         /* Just shy of the typical max heap size so that it will actually
     47          * try to allocate it instead of short-circuiting.
     48          *
     49          * TODO: stop assuming the VM defaults to 16MB max
     50          */
     51         final int SIXTEEN_MB = (16 * 1024 * 1024 - 32);
     52 
     53         Boolean sawEx = false;
     54         byte a[];
     55 
     56         try {
     57             a = new byte[SIXTEEN_MB];
     58         } catch (OutOfMemoryError oom) {
     59             //Log.i(TAG, "HeapTest/OomeLarge caught " + oom);
     60             sawEx = true;
     61         }
     62 
     63         if (!sawEx) {
     64             throw new RuntimeException("Test failed: " +
     65                     "OutOfMemoryError not thrown");
     66         }
     67 
     68         System.out.println("testOomeLarge succeeded");
     69     }
     70 
     71     /* Do this in another method so that the GC has a chance of freeing the
     72      * list afterwards.  Even if we null out list when we're done, the conservative
     73      * GC may see a stale pointer to it in a register.
     74      *
     75      * TODO: stop assuming the VM defaults to 16MB max
     76      */
     77     private static boolean testOomeSmallInternal() {
     78         final int SIXTEEN_MB = (16 * 1024 * 1024);
     79         final int LINK_SIZE = 6 * 4; // estimated size of a LinkedList's node
     80 
     81         LinkedList<Object> list = new LinkedList<Object>();
     82 
     83         /* Allocate progressively smaller objects to fill up the entire heap.
     84          */
     85         int objSize = 1 * 1024 * 1024;
     86         while (objSize >= LINK_SIZE) {
     87             boolean sawEx = false;
     88             try {
     89                 for (int i = 0; i < SIXTEEN_MB / objSize; i++) {
     90                     list.add((Object)new byte[objSize]);
     91                 }
     92             } catch (OutOfMemoryError oom) {
     93                 sawEx = true;
     94             }
     95 
     96             if (!sawEx) {
     97                 return false;
     98             }
     99 
    100             objSize = (objSize * 4) / 5;
    101         }
    102 
    103         return true;
    104     }
    105 
    106     private static void testOomeSmall() {
    107         System.out.println("testOomeSmall beginning");
    108         if (!testOomeSmallInternal()) {
    109             /* Can't reliably throw this from inside the internal function, because
    110              * we may not be able to allocate the RuntimeException.
    111              */
    112             throw new RuntimeException("Test failed: " +
    113                     "OutOfMemoryError not thrown while filling heap");
    114         }
    115         System.out.println("testOomeSmall succeeded");
    116     }
    117 }
    118