java.sql.SQLException: No suitable driver solution

  warning: com.mchange.v2.resourcepool.BasicResourcePool$ScatteredAcquireTask@5466b465 -- Acquisition Attempt Failed!!! Clearing pending acquires. While trying to acquire a needed new resource, we failed to succeed more than the maximum number of allowed acquisition attempts (30). Last acquisition attempt exception: 
java.sql.SQLException: No suitable driver
	at java.sql.DriverManager.getDriver(Unknown Source)
	at com.mchange.v2.c3p0.DriverManagerDataSource.driver(DriverManagerDataSource.java:285)
	at com.mchange.v2.c3p0.DriverManagerDataSource.getConnection(DriverManagerDataSource.java:161)
	at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:161)
	at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:147)
	at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool$1PooledConnectionResourcePoolManager.acquireResource(C3P0PooledConnectionPool.java:202)
	at com.mchange.v2.resourcepool.BasicResourcePool.doAcquire(BasicResourcePool.java:1138)
	at com.mchange.v2.resourcepool.BasicResourcePool.doAcquireAndDecrementPendingAcquiresWithinLockOnSuccess(BasicResourcePool.java:1125)
	at com.mchange.v2.resourcepool.BasicResourcePool.access$700(BasicResourcePool.java:44)
	at com.mchange.v2.resourcepool.BasicResourcePool$ScatteredAcquireTask.run(BasicResourcePool.java:1870)
	at com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run(ThreadPoolAsynchronousRunner.java:696)

//August 14, 2011:49:09 p.m. com.mchange.v2.resourcepool.BasicResourcePool 
//Warning: Having failed to acquire a resource, com.mchange.v2.resourcepool.BasicResourcePool@5fa258af is interrupting all Threads waiting on a resource to check out. Will try again in response to new client requests.
java.sql.SQLException: Connections could not be acquired from the underlying database!
	at com.mchange.v2.sql.SqlUtils.toSQLException(SqlUtils.java:118)
	at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool.checkoutPooledConnection(C3P0PooledConnectionPool.java:692)
	at com.mchange.v2.c3p0.impl.AbstractPoolBackedDataSource.getConnection(AbstractPoolBackedDataSource.java:140)
	at org.apache.commons.dbutils.AbstractQueryRunner.prepareConnection(AbstractQueryRunner.java:204)
	at org.apache.commons.dbutils.QueryRunner.query(QueryRunner.java:305)
	at com.qf.edu.dao.impl.StudentDaoImpl.findAll(StudentDaoImpl.java:21)
	at com.qf.edu.service.impl.StudentServiceImpl.findAll(StudentServiceImpl.java:22)
	at com.qf.edu.servlet.StudentListServlet.doGet(StudentListServlet.java:29)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:624)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:731)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
	at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:219)
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:110)
	at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:494)
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:169)
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:104)
	at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:1025)
	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:445)
	at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1137)
	at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:637)
	at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:317)
//August 14, 2011:49:09 p.m. com.mchange.v2.resourcepool.BasicResourcePool 
//Warning: com.mchange.v2.resourcepool.BasicResourcePool $Scattered AcquireTask@5e9edf15-Acquisition Attempt Failed!!!!! Clearing acquisitions. While trying to acquire a needed new resource, we failed to succeed more than the maximum number of allowed acquisition attempts (30). Last acquisition attempt: 
java.sql.SQLException: No suitable driver
	at java.sql.DriverManager.getDriver(Unknown Source)
	at com.mchange.v2.c3p0.DriverManagerDataSource.driver(DriverManagerDataSource.java:285)
	at com.mchange.v2.c3p0.DriverManagerDataSource.getConnection(DriverManagerDataSource.java:161)

A pit I met was also the result of my carelessness.

Let's start with some other solutions that you can often see on the Internet:

1. There is a good chance that the configuration file in c3p0-config.xml will have problems. Look for the configuration file carefully.

2. The mysql-connector-java-**-bin.jar package was not added to the storage location of the external jar package in the Java runtime environment. Or no Build Path.

3. Incompatible version of driver jar package

4.c3p0 configuration file is misplaced and placed in src root directory.

5. I made a mistake: I used a custom c3p0 configuration file with name attribute, but I did not add the value of name attribute to get the connection pool, resulting in java.sql.SQLException: No suitable driver.

6. If it is a custom c3p0 connection pool