How to use SMOTE in Java Weka API?
Welcome to the community.

You can use the following code:

import weka.filters.supervised.instance.SMOTE;
import weka.core.Instances;
import weka.core.converters.ConverterUtils.DataSource;
import weka.filters.Filter;

Instances data = DataSource.read(".../file.arff"); //Dataset 

SMOTE smote=new SMOTE();  //create object of SMOTE
smote.setInputFormat(data);
Instances data_smote = Filter.useFilter(data, smote); //Apply SMOTE on Dataset