code: public void close() throws IOException, QdbException {
  		this.compoundRegistry.close();
  		this.propertyRegistry.close();
  		this.descriptorRegistry.close();
  		this.modelRegistry.close();
  		this.predictionRegistry.close();
  
  		try {
  			this.storage.close();
  		} finally {
  			this.storage = null;
  		}
  
  		try {
  			if(this.tempDir != null){
  				FileUtil.deleteTempDirectory(this.tempDir);
  			}
  		} finally {
  			this.tempDir = null;
  		}
  	}
docs: Frees resources.