make StreamDBClient object implement AutoClosable

[elliVM]

Description

StreamDBClient implements AutoClosable with a close() method that closes the created JDBC Connection.

Checklists

Testing

Changes effect only objects internal operation no unit testing for non public operation.

General

• I have checked that my test files and functions have meaningful names.
• I have checked that each test tests only a single behavior.
• I have done happy tests.
• I have tested only my own code.
• I have tested at least all public methods.

Assertions

• I have checked that my tests use assertions and not runtime overhead.
• I have checked that my tests end in assertions.
• I have checked that there is no comparison statements in assertions.
• I have checked that assertions are in tests and not in helper functions.
• I have checked that assertions for iterables are outside of for loops and both sides of the iteration blocks.
• I have checked that assertions are not tested inside consumers.

Testing Data

• I have tested algorithms and anything else with the possibility of unbound growth.
• I have checked that all testing data is local and fully replaceable or reproducible or both.
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• I have checked that all test-specific fake objects and classes are in the test directory.
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• I have checked that my tests do not contain non-generic information.
• I have checked that my tests do not do external requests and are not privately or publicly routable.

Statements

• I have checked that my tests do not use throws for exceptions.
• I have checked that my tests do not use try-catch statements.
• I have checked that my tests do not use if-else statements.

Java

• I have checked that my tests for Java uses JUnit library.
• I have checked that my tests for Java uses JUnit utilities for parameters.

Other

• I have only tested public behavior and not private implementation details.
• I have checked that my tests are not (partially) commented out.
• I have checked that hand-crafted variables in assertions are used accordingly.
• I have tested Object Equality.
• I have checked that I do not have any manual tests or I have a valid reason for them and I have explained it in the PR description.

Code Quality

• I have checked that my code follows metrics set in Procedure: Class Metrics.
• I have checked that my code follows metrics set in Procedure: Method Metrics.
• I have checked that my code follows metrics set in Procedure: Object Quality.
• I have checked that my code does not have any NULL values.
• I have checked my code does not contain FIXME or TODO comments.

[elliVM]

rebased

[Tiihott]

Tests pass and changes look good. LGTM

[elliVM]

rebased