core/src/main/java/com/orientechnologies/orient/core/metadata/schema/OPropertyImpl.java
@Deprecated
  public OIndex<?> getIndex() {
    acquireSchemaReadLock();
    try {
      Set<OIndex<?>> indexes = owner.getInvolvedIndexes(globalRef.getName());
      if (indexes != null && !indexes.isEmpty())
        return indexes.iterator().next();
      return null;
    } finally {
      releaseSchemaReadLock();
    }
  }
@Deprecated
  public OIndex<?> getIndex() {
    acquireSchemaReadLock();
    try {
      Set<OIndex<?>> indexes = owner.getInvolvedIndexes(globalRef.getName());
      if (indexes != null && !indexes.isEmpty())
        return indexes.iterator().next();
      return null;
    } finally {
      releaseSchemaReadLock();
    }
  }
Returns the first index defined for the property.

@deprecated Use {@link OClass#getInvolvedIndexes(String...)} instead.