To persist an instance of

class MyData implements Serializable{
	//...
}

create a Prevayler for it:

Prevayler<MyData> prevayler = PrevaylerFactory.createPrevayler(new MyData());

and ensure any changes to it are made via the local variable in Transactions:

class MyChange implements org.prevayler.Transaction<MyData>{
	public void executeOn(MyData myData, Date date){
		//make any changes via "myData" here
	}
}

//execute a "MyChange":
prevayler.execute(new MyChange());

You can pass arguments into a Transaction:

//execute a "MyChange"
prevayler.execute(new MyChange(new MyArgument()));

via one or more instance variables in your Transaction:

class MyChange implements Transaction<MyData>{
	
	MyArgument myArgument;
	
	public MyChange(MyArgument myArgument){
		this.myArgument = myArgument;
	}

	public void executeOn(MyData myData, Date date){
		//You can use "myArgument" here, but upon
		//recovery execution it'll be a freshly
		//deserialized copy, so it won't reference
		//anything in "myData"
	}
}

To perform a Transaction with a query, implement TransactionWithQuery and set the second type parameter to your desired return type:

class MyChangeAndQuery implements TransactionWithQuery<MyData, MyReturnType>{
	public MyReturnType executeAndQuery(MyData myData, Date date){
		MyReturnType queryResult;
		//...
		return queryResult;
	}
}

//perform a "MyChangeAndQuery" and get the result
MyReturnType queryResult = prevayler.execute(new MyChangeAndQuery());

You can also perform a straightforward Query (which won't write any transaction to disk) or a SureTransactionWithQuery (which doesn't throw Exception).

You may want to write a snapshot of your persistent object to disk from time to time, to shorten recovery time upon system restart:

prevayler.takeSnapshot();