[jvm-packages] xgboost4j_2.12-1.2.0.jar contains wrong version of libxgboost4j.so

[hcho3]

#5957 (comment)

The 1.2.0 JAR file from Maven Central contains 1.0.2 version of libxgboost4j.so. You can test it by downloading xgboost4j_2.12-1.2.0.jar, extracting libxgboost4j.so, and then running the following Python script:

import ctypes

lib = ctypes.cdll.LoadLibrary('./libxgboost4j.so')

major = ctypes.c_int()
minor = ctypes.c_int()
patch = ctypes.c_int()

lib.XGBoostVersion(ctypes.byref(major), ctypes.byref(minor), ctypes.byref(patch))
print((major.value, minor.value, patch.value))  # prints (1, 0, 2), indicating version 1.0.2

The 1.1.1 version of xgboost4j (xgboost4j_2.12-1.1.0.jar) has the same problem.

On the other hand, the xgboost4j-gpu package does not suffer from the problem: xgboost4j-gpu_2.12-1.2.0.jar has the latest libxgboost4j.so with relevant GPU code in it.

[hcho3]

cc @CodingCat @wbo4958 @trivialfis

[CodingCat]

oh, s**t...I checked the problem is real but I cannot think out why it looks like this, I would propose release 1.2.1 and 1.1.2 in jvm-packages as hot fix and I will work on a one-click script to automate everything, seems those manual steps are error-prone

[hcho3]

Let's also think about what we can automated on the CI side.

[trivialfis]

@hcho3 @CodingCat Can we close this one?

[hcho3]

1.2.1 patch release is now up on Maven Central: https://mvnrepository.com/artifact/ml.dmlc/xgboost4j