driver-legacy/src/main/com/mongodb/DBCollection.java
public void dropIndex(final String indexName) {
        try {
            executor.execute(new DropIndexOperation(getNamespace(), indexName, getWriteConcern()), getReadConcern());
        } catch (MongoWriteConcernException e) {
            throw createWriteConcernException(e);
        }
    }
public void dropIndex(final String indexName) {
        try {
            executor.execute(new DropIndexOperation(getNamespace(), indexName, getWriteConcern()), getReadConcern());
        } catch (MongoWriteConcernException e) {
            throw createWriteConcernException(e);
        }
    }
public void dropIndex ( final String indexName ) { try { executor . execute ( new DropIndexOperation ( getNamespace ( ) , indexName , getWriteConcern ( ) ) , getReadConcern ( ) ) ; } catch ( MongoWriteConcernException e ) { throw createWriteConcernException ( e ) ; } }
Drops the index with the given name from this collection.

@param indexName name of index to drop
@throws MongoException if the index does not exist
@mongodb.driver.manual core/indexes/ Indexes
Drops the index with the given name from this collection .