A null pointer is reported when the mvn test command is executed in the joyqueue-client/joyqueue-client-loadbalance-adaptive directory.

v4.2.7 A null pointer is reported when the mvn test command is executed in the joyqueue-client/joyqueue-client-loadbalance-adaptive directory.
[INFO] Running org.joyqueue.client.loadbalance.adaptive.AdaptiveLoadBalanceTest
[ERROR] Tests run: 8, Failures: 0, Errors: 4, Skipped: 0, Time elapsed: 3.652 s <<< FAILURE! - in org.joyqueue.client.loadbalance.adaptive.AdaptiveLoadBalanceTest
[ERROR] regionTest(org.joyqueue.client.loadbalance.adaptive.AdaptiveLoadBalanceTest) Time elapsed: 1.417 s <<< ERROR!
java.lang.NullPointerException
at org.joyqueue.client.loadbalance.adaptive.AdaptiveLoadBalanceTest.regionTest(AdaptiveLoadBalanceTest.java:87)

[ERROR] simpleTest(org.joyqueue.client.loadbalance.adaptive.AdaptiveLoadBalanceTest) Time elapsed: 0.377 s <<< ERROR!
java.lang.NullPointerException
at org.joyqueue.client.loadbalance.adaptive.AdaptiveLoadBalanceTest.simpleTest(AdaptiveLoadBalanceTest.java:77)

[ERROR] customJudgeTest(org.joyqueue.client.loadbalance.adaptive.AdaptiveLoadBalanceTest) Time elapsed: 0.391 s <<< ERROR!
java.lang.NullPointerException
at org.joyqueue.client.loadbalance.adaptive.AdaptiveLoadBalanceTest.customJudgeTest(AdaptiveLoadBalanceTest.java:133)

[ERROR] regionAndErrorTest(org.joyqueue.client.loadbalance.adaptive.AdaptiveLoadBalanceTest) Time elapsed: 0.349 s <<< ERROR!
java.lang.NullPointerException
at org.joyqueue.client.loadbalance.adaptive.AdaptiveLoadBalanceTest.regionAndErrorTest(AdaptiveLoadBalanceTest.java:112)

Run mvn test from joyqueue-client/joyqueue-client-loadbalance-adaptive and inspect org.joyqueue.client.loadbalance.adaptive.AdaptiveLoadBalanceTest at lines 77, 87, 112, and 133. Trace the null values behind the four failures and verify that the adaptive load-balance tests complete without NullPointerException.

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