BAEL-1818 A Simple Guide to Connection Pooling in Java (#4823)

* Initial Commit

* Update parent pom.xml

* Update BasicConnectionPool class

* Update BasicConnectionPool class

* BAEL-1818 removed code from core-java module, cleaned up a little pom files

* BAEL-1818 moved the code from connectionpool.connectionpools package to connectionpool

core-java/src/test/java/com/baeldung/connectionpool/BasicConnectionPoolUnitTest.java

@@ -1,69 +0,0 @@
-package com.baeldung.connectionpool;
-
-import com.baeldung.connectionpool.connectionpools.BasicConnectionPool;
-import com.baeldung.connectionpool.connectionpools.ConnectionPool;
-import java.sql.Connection;
-import java.sql.SQLException;
-import java.util.List;
-import static org.assertj.core.api.Assertions.assertThat;
-import static org.junit.Assert.assertTrue;
-import static org.junit.Assert.fail;
-
-import org.junit.BeforeClass;
-import org.junit.Test;
-
-public class BasicConnectionPoolUnitTest {
-    
-    private static ConnectionPool connectionPool;
-
-    @BeforeClass
-    public static void setUpBasicConnectionPoolInstance() throws SQLException {
-        connectionPool = BasicConnectionPool.create("jdbc:h2:mem:test", "user", "password");
-    }
-    
-    @Test
-    public void givenBasicConnectionPoolInstance_whenCalledgetConnection_thenCorrect() throws Exception {
-        assertTrue(connectionPool.getConnection().isValid(1));
-    }
-    
-    @Test
-    public void givenBasicConnectionPoolInstance_whenCalledreleaseConnection_thenCorrect() throws Exception {
-        Connection connection = connectionPool.getConnection();
-        assertThat(connectionPool.releaseConnection(connection)).isTrue();
-    }
-    
-    @Test
-    public void givenBasicConnectionPoolInstance_whenCalledgetUrl_thenCorrect() {
-        assertThat(connectionPool.getUrl()).isEqualTo("jdbc:h2:mem:test");
-    }
-    
-    @Test
-    public void givenBasicConnectionPoolInstance_whenCalledgetUser_thenCorrect() {
-        assertThat(connectionPool.getUser()).isEqualTo("user");
-    }
-    
-    @Test
-    public void givenBasicConnectionPoolInstance_whenCalledgetPassword_thenCorrect() {
-        assertThat(connectionPool.getPassword()).isEqualTo("password");
-    }
-
-    @Test(expected = RuntimeException.class)
-    public void givenBasicConnectionPoolInstance_whenAskedForMoreThanMax_thenError() throws Exception {
-        // this test needs to be independent so it doesn't share the same connection pool as other tests
-        ConnectionPool cp = BasicConnectionPool.create("jdbc:h2:mem:test", "user", "password");
-        final int MAX_POOL_SIZE = 20;
-        for (int i = 0; i < MAX_POOL_SIZE + 1; i++) {
-            cp.getConnection();
-        }
-        fail();
-    }
-
-    @Test
-    public void givenBasicConnectionPoolInstance_whenSutdown_thenEmpty() throws Exception {
-        ConnectionPool cp = BasicConnectionPool.create("jdbc:h2:mem:test", "user", "password");
-        assertThat(((BasicConnectionPool)cp).getSize()).isEqualTo(10);
-
-        ((BasicConnectionPool) cp).shutdown();
-        assertThat(((BasicConnectionPool)cp).getSize()).isEqualTo(0);
-    }
-}

core-java/src/test/java/com/baeldung/connectionpool/C3poDataSourceUnitTest.java

@@ -1,14 +0,0 @@
-package com.baeldung.connectionpool;
-
-import com.baeldung.connectionpool.connectionpools.C3poDataSource;
-import java.sql.SQLException;
-import static org.junit.Assert.assertTrue;
-import org.junit.Test;
-
-public class C3poDataSourceUnitTest {
-    
-    @Test
-    public void givenC3poDataSourceClass_whenCalledgetConnection_thenCorrect() throws SQLException {
-        assertTrue(C3poDataSource.getConnection().isValid(1));
-    }   
-}

core-java/src/test/java/com/baeldung/connectionpool/DBCPDataSourceUnitTest.java

@@ -1,14 +0,0 @@
-package com.baeldung.connectionpool;
-
-import com.baeldung.connectionpool.connectionpools.DBCPDataSource;
-import java.sql.SQLException;
-import static org.junit.Assert.assertTrue;
-import org.junit.Test;
-
-public class DBCPDataSourceUnitTest {
-    
-    @Test
-    public void givenDBCPDataSourceClass_whenCalledgetConnection_thenCorrect() throws SQLException {
-        assertTrue(DBCPDataSource.getConnection().isValid(1));
-    }   
-}

core-java/src/test/java/com/baeldung/connectionpool/HikariCPDataSourceUnitTest.java

@@ -1,14 +0,0 @@
-package com.baeldung.connectionpool;
-
-import com.baeldung.connectionpool.connectionpools.HikariCPDataSource;
-import java.sql.SQLException;
-import static org.junit.Assert.assertTrue;
-import org.junit.Test;
-
-public class HikariCPDataSourceUnitTest {
-    
-    @Test
-    public void givenHikariDataSourceClass_whenCalledgetConnection_thenCorrect() throws SQLException {
-        assertTrue(HikariCPDataSource.getConnection().isValid(1));
-    }   
-}