Java cannot access MySQL

I am running ubuntu 20.04 and I need to run the java-based Floreant POS which connects to MySQL. I already have MySQL setup and installed mysql-connector-java_8.0.23-1ubuntu20.04_all.deb

When I start the POS by running java -jar floreantpos.jar from shell, I was directed to the database setup page which I entered the mysql info, the software said "Connection Failed".

Below is the runtime output from my shell

java -cp floreantpos.jar com.floreantpos.main.SetUpWindow  WARNING: An illegal reflective access operation has occurred  WARNING: Illegal reflective access by org.dom4j.io.SAXContentHandler (file:/home/username/Downloads/flor/lib/dom4j-1.6.1.jar) to method com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser$LocatorProxy.getEncoding()  WARNING: Please consider reporting this to the maintainers of org.dom4j.io.SAXContentHandler  WARNING: Use --illegal-access=warn to enable warnings of further illegal reflective access operations  WARNING: All illegal access operations will be denied in a future release  ERROR: 30-Mar-2021 09:55:00: could not get database metadata  java.sql.SQLException: Connections could not be acquired from the underlying database!      at com.mchange.v2.sql.SqlUtils.toSQLException(SqlUtils.java:106)      at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool.checkoutPooledConnection(C3P0PooledConnectionPool.java:529)      at com.mchange.v2.c3p0.impl.AbstractPoolBackedDataSource.getConnection(AbstractPoolBackedDataSource.java:128)      at org.hibernate.connection.C3P0ConnectionProvider.getConnection(C3P0ConnectionProvider.java:56)      at org.hibernate.tool.hbm2ddl.SuppliedConnectionProviderConnectionHelper.prepare(SuppliedConnectionProviderConnectionHelper.java:27)      at org.hibernate.tool.hbm2ddl.SchemaUpdate.execute(SchemaUpdate.java:127)      at org.hibernate.impl.SessionFactoryImpl.<init>(SessionFactoryImpl.java:314)      at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1300)      at com.floreantpos.util.DatabaseUtil.checkConnection(DatabaseUtil.java:97)      at com.floreantpos.util.DatabaseUtil.checkConnection(DatabaseUtil.java:87)      at com.floreantpos.main.SetUpWindow.actionPerformed(SetUpWindow.java:374)      at java.desktop/javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:1967)      at java.desktop/javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2308)      at java.desktop/javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:405)      at java.desktop/javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:262)      at java.desktop/javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:279)      at java.desktop/java.awt.Component.processMouseEvent(Component.java:6635)      at java.desktop/javax.swing.JComponent.processMouseEvent(JComponent.java:3342)      at java.desktop/java.awt.Component.processEvent(Component.java:6400)      at java.desktop/java.awt.Container.processEvent(Container.java:2263)      at java.desktop/java.awt.Component.dispatchEventImpl(Component.java:5011)      at java.desktop/java.awt.Container.dispatchEventImpl(Container.java:2321)      at java.desktop/java.awt.Component.dispatchEvent(Component.java:4843)      at java.desktop/java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4918)      at java.desktop/java.awt.LightweightDispatcher.processMouseEvent(Container.java:4547)      at java.desktop/java.awt.LightweightDispatcher.dispatchEvent(Container.java:4488)      at java.desktop/java.awt.Container.dispatchEventImpl(Container.java:2307)      at java.desktop/java.awt.Window.dispatchEventImpl(Window.java:2772)      at java.desktop/java.awt.Component.dispatchEvent(Component.java:4843)      at java.desktop/java.awt.EventQueue.dispatchEventImpl(EventQueue.java:772)      at java.desktop/java.awt.EventQueue$4.run(EventQueue.java:721)      at java.desktop/java.awt.EventQueue$4.run(EventQueue.java:715)      at java.base/java.security.AccessController.doPrivileged(Native Method)      at java.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:85)      at java.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:95)      at java.desktop/java.awt.EventQueue$5.run(EventQueue.java:745)      at java.desktop/java.awt.EventQueue$5.run(EventQueue.java:743)      at java.base/java.security.AccessController.doPrivileged(Native Method)      at java.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:85)      at java.desktop/java.awt.EventQueue.dispatchEvent(EventQueue.java:742)      at java.desktop/java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:203)      at java.desktop/java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:124)      at java.desktop/java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:113)      at java.desktop/java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:109)      at java.desktop/java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)      at java.desktop/java.awt.EventDispatchThread.run(EventDispatchThread.java:90)  Caused by: com.mchange.v2.resourcepool.CannotAcquireResourceException: A ResourcePool could not acquire a resource from its primary factory or source.      at com.mchange.v2.resourcepool.BasicResourcePool.awaitAvailable(BasicResourcePool.java:1319)      at com.mchange.v2.resourcepool.BasicResourcePool.prelimCheckoutResource(BasicResourcePool.java:557)      at com.mchange.v2.resourcepool.BasicResourcePool.checkoutResource(BasicResourcePool.java:477)      at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool.checkoutPooledConnection(C3P0PooledConnectionPool.java:525)      ... 44 more  ERROR: 30-Mar-2021 09:55:00: could not complete schema update  java.sql.SQLException: Connections could not be acquired from the underlying database!      at com.mchange.v2.sql.SqlUtils.toSQLException(SqlUtils.java:106)      at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool.checkoutPooledConnection(C3P0PooledConnectionPool.java:529)      at com.mchange.v2.c3p0.impl.AbstractPoolBackedDataSource.getConnection(AbstractPoolBackedDataSource.java:128)      at org.hibernate.connection.C3P0ConnectionProvider.getConnection(C3P0ConnectionProvider.java:56)      at org.hibernate.tool.hbm2ddl.SuppliedConnectionProviderConnectionHelper.prepare(SuppliedConnectionProviderConnectionHelper.java:27)      at org.hibernate.tool.hbm2ddl.SchemaUpdate.execute(SchemaUpdate.java:127)      at org.hibernate.impl.SessionFactoryImpl.<init>(SessionFactoryImpl.java:314)      at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1300)      at com.floreantpos.util.DatabaseUtil.checkConnection(DatabaseUtil.java:97)      at com.floreantpos.util.DatabaseUtil.checkConnection(DatabaseUtil.java:87)      at com.floreantpos.main.SetUpWindow.actionPerformed(SetUpWindow.java:374)      at java.desktop/javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:1967)      at java.desktop/javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2308)      at java.desktop/javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:405)      at java.desktop/javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:262)      at java.desktop/javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:279)      at java.desktop/java.awt.Component.processMouseEvent(Component.java:6635)      at java.desktop/javax.swing.JComponent.processMouseEvent(JComponent.java:3342)      at java.desktop/java.awt.Component.processEvent(Component.java:6400)      at java.desktop/java.awt.Container.processEvent(Container.java:2263)      at java.desktop/java.awt.Component.dispatchEventImpl(Component.java:5011)      at java.desktop/java.awt.Container.dispatchEventImpl(Container.java:2321)      at java.desktop/java.awt.Component.dispatchEvent(Component.java:4843)      at java.desktop/java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4918)      at java.desktop/java.awt.LightweightDispatcher.processMouseEvent(Container.java:4547)      at java.desktop/java.awt.LightweightDispatcher.dispatchEvent(Container.java:4488)      at java.desktop/java.awt.Container.dispatchEventImpl(Container.java:2307)      at java.desktop/java.awt.Window.dispatchEventImpl(Window.java:2772)      at java.desktop/java.awt.Component.dispatchEvent(Component.java:4843)      at java.desktop/java.awt.EventQueue.dispatchEventImpl(EventQueue.java:772)      at java.desktop/java.awt.EventQueue$4.run(EventQueue.java:721)      at java.desktop/java.awt.EventQueue$4.run(EventQueue.java:715)      at java.base/java.security.AccessController.doPrivileged(Native Method)      at java.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:85)      at java.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:95)      at java.desktop/java.awt.EventQueue$5.run(EventQueue.java:745)      at java.desktop/java.awt.EventQueue$5.run(EventQueue.java:743)      at java.base/java.security.AccessController.doPrivileged(Native Method)      at java.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:85)      at java.desktop/java.awt.EventQueue.dispatchEvent(EventQueue.java:742)      at java.desktop/java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:203)      at java.desktop/java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:124)      at java.desktop/java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:113)      at java.desktop/java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:109)      at java.desktop/java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)      at java.desktop/java.awt.EventDispatchThread.run(EventDispatchThread.java:90)  Caused by: com.mchange.v2.resourcepool.CannotAcquireResourceException: A ResourcePool could not acquire a resource from its primary factory or source.      at com.mchange.v2.resourcepool.BasicResourcePool.awaitAvailable(BasicResourcePool.java:1319)      at com.mchange.v2.resourcepool.BasicResourcePool.prelimCheckoutResource(BasicResourcePool.java:557)      at com.mchange.v2.resourcepool.BasicResourcePool.checkoutResource(BasicResourcePool.java:477)      at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool.checkoutPooledConnection(C3P0PooledConnectionPool.java:525)      ... 44 more  ERROR: 30-Mar-2021 09:55:00: Connections could not be acquired from the underlying database!  

Seems like java is not able to connect to MySQL. My MySQL setup is pretty standard: MySQL address: localhost Port: 3306

https://stackoverflow.com/questions/66863870/java-cannot-access-mysql March 30, 2021 at 10:07AM