Once you have enabled transactions for your environment and your databases, you can use them to protect your database operations. You do this by acquiring a transaction handle and then using that handle for any database operation that you want to participate in that transaction.

You obtain a transaction handle using the Environment.beginTransaction() method.

Once you have completed all of the operations that you want to include in the transaction, you must commit the transaction using the Transaction.commit() method.

If, for any reason, you want to abandon the transaction, you abort it using Transaction.abort().

Any transaction handle that has been committed or aborted can no longer be used by your application.

Finally, you must make sure that all transaction handles are either committed or aborted before closing your databases and environment.

For example, the following example opens a transactional-enabled environment and store, obtains a transaction handle, and then performs a write operation under its protection. In the event of any failure in the write operation, the transaction is aborted and the store is left in a state as if no operations had ever been attempted in the first place.

package persist.txn;

import com.sleepycat.db.DatabaseException;
import com.sleepycat.db.Environment;
import com.sleepycat.db.EnvironmentConfig;
import com.sleepycat.db.Transaction;

import com.sleepycat.persist.EntityStore;
import com.sleepycat.persist.StoreConfig;

import java.io.File;
import java.io.FileNotFoundException;

...

Environment myEnv = null;
EntityStore store = null;

// Our convenience data accessor class, used for easy access to 
// EntityClass indexes.
DataAccessor da;

try {
    EnvironmentConfig myEnvConfig = new EnvironmentConfig();
    myEnvConfig.setInitializeCache(true);
    myEnvConfig.setInitializeLocking(true);
    myEnvConfig.setInitializeLogging(true);
    myEnvConfig.setTransactional(true);

    StoreConfig storeConfig = new StoreConfig();
    storeConfig.setTransactional(true);

    myEnv = new Environment(new File("/my/env/home"),
                              myEnvConfig);

    EntityStore store = new EntityStore(myEnv, 
                             "EntityStore", storeConfig);

    da = new DataAccessor(store);

    // Assume that Inventory is an entity class.
    Inventory theInventory = new Inventory();
    theInventory.setItemName("Waffles");
    theInventory.setItemSku("waf23rbni");

    Transaction txn = myEnv.beginTransaction(null, null);
        
    try {
        // Put the object to the store using the transaction handle.
        da.inventoryBySku.put(txn, theInventory);

        // Commit the transaction. The data is now safely written to the
        // store.
        txn.commit();
    // If there is a problem, abort the transaction
    } catch (Exception e) {
        if (txn != null) {
            txn.abort();
            txn = null;
        }
    }


} catch (DatabaseException de) {
    // Exception handling goes here
    } catch (FileNotFoundException fnfe) {
    // Exception handling goes here
}

The same thing can be done with the base API; the database in use is left unchanged if the write operation fails:

package db.txn;

import com.sleepycat.db.Database;
import com.sleepycat.db.DatabaseConfig;
import com.sleepycat.db.DatabaseEntry;
import com.sleepycat.db.DatabaseException;
import com.sleepycat.db.Environment;
import com.sleepycat.db.EnvironmentConfig;
import com.sleepycat.db.Transaction;

import java.io.File;
import java.io.FileNotFoundException;

...

Database myDatabase = null;
Environment myEnv = null;
try {
    EnvironmentConfig myEnvConfig = new EnvironmentConfig();
    myEnvConfig.setInitializeCache(true);
    myEnvConfig.setInitializeLocking(true);
    myEnvConfig.setInitializeLogging(true);
    myEnvConfig.setTransactional(true);

    myEnv = new Environment(new File("/my/env/home"),
                              myEnvConfig);

    // Open the database.
    DatabaseConfig dbConfig = new DatabaseConfig();
    dbConfig.setTransactional(true);
    dbConfig.setType(DatabaseType.BTREE);
    myDatabase = myEnv.openDatabase(null,              // txn handle
                                    "sampleDatabase",  // db file name
                                    null,              // db name
                                    dbConfig);
    String keyString = "thekey";
    String dataString = "thedata";
    DatabaseEntry key = 
        new DatabaseEntry(keyString.getBytes("UTF-8"));
    DatabaseEntry data = 
        new DatabaseEntry(dataString.getBytes("UTF-8"));

    Transaction txn = myEnv.beginTransaction(null, null);
        
    try {
        myDatabase.put(txn, key, data);
        txn.commit();
    } catch (Exception e) {
        if (txn != null) {
            txn.abort();
            txn = null;
        }
    }

} catch (DatabaseException de) {
    // Exception handling goes here
} catch (FileNotFoundException fnfe) {
    // Exception handling goes here
}