skywalking-log com.ai.cloud 1.0b 4.0.0 example jar example http://maven.apache.org UTF-8 junit junit 3.8.1 test log4j log4j 1.2.17 test org.apache.logging.log4j log4j-core 2.4.1 test com.ai.cloud skywalking-log4j-2.x-plugin 1.0b com.ai.cloud skywalking-log4j-1.x-plugin 1.0b