stmt.executeUpdate("PRAGMA synchronous = OFF;");

java.sql.SQLException: Safety level may not be changed inside a transaction
   at org.sqlite.DB.throwex(DB.java:252)
   at org.sqlite.NativeDB.prepare(Native Method)
   at org.sqlite.DB.prepare(DB.java:62)
   at org.sqlite.Stmt.executeUpdate(Stmt.java:82)
   at com.mchange.v2.c3p0.impl.NewProxyStatement.executeUpdate(NewProxyStatement.java:64)

stmt.executeUpdate("PRAGMA synchronous = OFF;");

testConnectionOnCheckout
    Default: false
    Use only if necessary. Expensive. If true, an operation will be performed at every connection checkout to verify that the connection is valid. Better choice: verify connections periodically using idleConnectionTestPeriod. Also, setting an automaticTestTable or preferredTestQuery will usually speed up all connection tests. [See "Configuring Connection Testing"]

preferredTestQuery
    Default: null
    Defines the query that will be executed for all connection tests, if the default ConnectionTester (or some other implementation of QueryConnectionTester, or better yet FullQueryConnectionTester) is being used. Defining a preferredTestQuery that will execute quickly in your database may dramatically speed up Connection tests. (If no preferredTestQuery is set, the default ConnectionTester executes a getTables() call on the Connection's DatabaseMetaData. Depending on your database, this may execute more slowly than a "normal" database query.) NOTE: The table against which your preferredTestQuery will be run must exist in the database schema prior to your initialization of your DataSource. If your application defines its own schema, try automaticTestTable instead. [See "Configuring Connection Testing"]