Currently, we use `UtFrameUtils` to start a FE server in the FE unit test.
Each test class has to do some initialization and clean up stuff with the JUnit4
`@BeforeClass` and `@AfterClass` annotation. It's redundant and boring.
Besides, almost all the APIs in `UtFrameUtils` has a `ConnectContext` parameter, which is not easy to use.
This PR proposes to use an inherit-manner, i.e., wrap all the common logic in base class `TestWithFeService`,
leveraging the
JUnit5 `@BeforeAll` and `@AfterAll` annotation to narrow down the setup and cleanup lifecycle to each test class instance.
At the same time, the derived concrete test class could directly use utility methods inherited from the base class,
without calling a util class and passing a `ConnectContext` argument.
`UtFrameUtils` and `DorisAssert` are marked as deprecated. We could remove these two classes
if this refactor works well for a time.
This feature is propsoed in [DSIP-1](https://cwiki.apache.org/confluence/display/DORIS/DSIP-001%3A+Java+UDF).
This PR support fixed-length input and output Java UDF. Phase I in DIP-1 is done after this PR.
To support Java UDF effeciently, I use no data copy in JNI call and all compute operations are off-heap in Java.
To achieve that, I use a UdfExecutor instead.
For users, a UDF class must have a public evaluate method.
