IndexOutOfBoundsException in LinkedList

Question

I'm getting IndexOutOfBoundsException, which looks like kind of impossible to me.

Code:

public class SomethingCalculator {

    @Nullable
    private Config mConfig;
    @Nullable
    private Long mTime;
    final private List<Long> mLinkedList = new LinkedList<>();


    public synchronized void setupWithConfiguration(Config config, Long time) {
        //config and time are non null always
        mTime = time;
        mConfig = config;
        generatLookUp();
    }


    public synchronized void reset() {
        mConfig = null;
        mTime = null;
        mLinkedList.clear();
    }


    @Nullable
    public synchronized Long getTheValue(long ms) {
        if (mConfig == null)
            return null;

        // getting exception here
        if (ms > mLinkedList.get(mLinkedList.size() - 1)) {
            return 0l; // something
        }
        return 0l; // something
    }


    private synchronized void generatLookUp() {
        mLinkedList.clear();
        if (mConfig == null || mTime==null)
            return;
        // mLinkedList will always have size > 0 after executing this
        // based upon config this method add elements to mLinkedList

        // adding dummy values
        mLinkedList.add(1L);
        mLinkedList.add(2L);
    }
}

getting an exception while calling SomethingCalculator.getTheValue()

Exception:

Fatal Exception: java.lang.IndexOutOfBoundsException: Index: 4, Size: 0
 at java.util.LinkedList.checkElementIndex(LinkedList.java:565)

Not sure if mMylinkedList.size() returns 4 then how mMylinkedList.get(4) throws IndexOutOfBoundsException.

Answer 1

After looking into generated AAR it was found that the synchronized keyword was stripped thus this exception can occur. The synchronized keyword was stripped due to a proguard optimization.

Removed this:

-optimizations !method/marking/synchronized

Now i can see synchronized keyword in the generated AAR.