@Override
  public String toString() {
    return "Partitioned Region " + "@"
        + Integer.toHexString(hashCode()) + " [" + "path='" + getFullPath()
        + "'; dataPolicy=" + getDataPolicy() + "; prId="
        + partitionedRegionId + "; isDestroyed=" + isDestroyed
        + "; isClosed=" + isClosed + "; retryTimeout="
        + retryTimeout + "; serialNumber=" + getSerialNumber()
        + "; partition attributes=" + getPartitionAttributes().toString()
        + "; on VM " + getMyId() + "]";
  }
Ask the grantor who has the lock

@return the ID of the member holding the lock
geode-core/src/main/java/org/apache/geode/internal/cache/PartitionedRegion.java