ArrayList之removeAll底层原理实现详解

        CollectionTest collectionTest =new CollectionTest();
        List<DataDto> list1 =new ArrayList<>();
        for(int i=1;i<=10;i++){
            DataDto dataDto =new DataDto(i+"");
            list1.add(dataDto);
        }
        List<DataDto> list2 =new ArrayList<>();
        DataDto dataDto1 =new DataDto("2");
        list2.add(dataDto1);
        list1.removeAll(list2);
        collectionTest.print(list1);

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        CollectionTest collectionTest =new CollectionTest();
        List<DataDto> list1 =new ArrayList<>();
        for(int i=1;i<=10;i++){
            DataDto dataDto =new DataDto(i+"");
            list1.add(dataDto);
        }
        List<DataDto> list2 =list1.subList(0,2);
        list1.removeAll(list2);
        collectionTest.print(list1);

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public boolean removeAll(Collection<?> c) {
        Objects.requireNonNull(c);
        return batchRemove(c, false);
}
    
private boolean batchRemove(Collection<?> c, boolean complement) {
        final Object[] elementData = this.elementData;
        int r = 0, w = 0;
        boolean modified = false;
        try {
            for (; r < size; r++)
                if (c.contains(elementData[r]) == complement)
                    elementData[w++] = elementData[r];
        } finally {
            // Preserve behavioral compatibility with AbstractCollection,
            // even if c.contains() throws.
            if (r != size) {
                System.arraycopy(elementData, r,
                                 elementData, w,
                                 size - r);
                w += size - r;
            }
            if (w != size) {
                // clear to let GC do its work
                for (int i = w; i < size; i++)
                    elementData[i] = null;
                modCount += size - w;
                size = w;
                modified = true;
            }
        }
        return modified;
    }