| Name | Description | Type | Package | Framework |
| ArrayMath | Utility class for simple vector arithmetic. | Class | opennlp.tools.ml.maxent.quasinewton | Natural Language Processing (OpenNLP) |
| Function | Interface | opennlp.tools.ml.maxent.quasinewton | Natural Language Processing (OpenNLP) | |
| LineSearch | Class | opennlp.tools.ml.maxent.quasinewton | Natural Language Processing (OpenNLP) | |
| LineSearch .LineSearchResult | Class | opennlp.tools.ml.maxent.quasinewton.LineSearch | Natural Language Processing (OpenNLP) | |
| NegLogLikelihood | Evaluate negative log-likelihood and its gradient from DataIndexer. | Class | opennlp.tools.ml.maxent.quasinewton | Natural Language Processing (OpenNLP) |
| ParallelNegLogLikelihood | Class | opennlp.tools.ml.maxent.quasinewton | Natural Language Processing (OpenNLP) | |
| QNMinimizer | and Elastic Net for solving convex optimization problems. | Class | opennlp.tools.ml.maxent.quasinewton | Natural Language Processing (OpenNLP) |
| QNMinimizer .Evaluator | Evaluate quality of training parameters. | Interface | opennlp.tools.ml.maxent.quasinewton.QNMinimizer | Natural Language Processing (OpenNLP) |
| QNMinimizer .L2RegFunction | Class | opennlp.tools.ml.maxent.quasinewton.QNMinimizer | Natural Language Processing (OpenNLP) | |
| QNModel | Class | opennlp.tools.ml.maxent.quasinewton | Natural Language Processing (OpenNLP) | |
| QNTrainer | Maxent model trainer using L-BFGS algorithm. | Class | opennlp.tools.ml.maxent.quasinewton | Natural Language Processing (OpenNLP) |