问题一：各位Flink Standalone模式 报这种错有遇到过吗？
各位Flink Standalone模式 报这种错有遇到过吗？ 
参考答案：
看着像你的flat map出了问题，跟模式没关系 ，
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问题二：大家遇到过Flink这个问题嘛？
大家遇到过Flink这个问题嘛？从检查点恢复不了Caused by: org.apache.flink.util.FlinkException: Could not restore keyed state backend for StreamingJoinOperator19d6b71338107590e1e4e7f82698bef0(1/2) from any of the 1 provided restore options.
at org.apache.flink.streaming.api.operators.BackendRestorerProcedure.createAndRestore(BackendRestorerProcedure.java:160)
at org.apache.flink.streaming.api.operators.StreamTaskStateInitializerImpl.keyedStatedBackend(StreamTaskStateInitializerImpl.java:346)
at org.apache.flink.streaming.api.operators.StreamTaskStateInitializerImpl.streamOperatorStateContext(StreamTaskStateInitializerImpl.java:164)
... 11 more
Caused by: org.apache.flink.runtime.state.BackendBuildingException: Caught unexpected exception.
at org.apache.flink.contrib.streaming.state.RocksDBKeyedStateBackendBuilder.build(RocksDBKeyedStateBackendBuilder.java:395)
at org.apache.flink.contrib.streaming.state.EmbeddedRocksDBStateBackend.createKeyedStateBackend(EmbeddedRocksDBStateBackend.java:483)
at org.apache.flink.contrib.streaming.state.EmbeddedRocksDBStateBackend.createKeyedStateBackend(EmbeddedRocksDBStateBackend.java:97)
at org.apache.flink.streaming.api.operators.StreamTaskStateInitializerImpl.lambda$keyedStatedBackend$1(StreamTaskStateInitializerImpl.java:329)
at org.apache.flink.streaming.api.operators.BackendRestorerProcedure.attemptCreateAndRestore(BackendRestorerProcedure.java:168)
at org.apache.flink.streaming.api.operators.BackendRestorerProcedure.createAndRestore(BackendRestorerProcedure.java:135)
... 13 more
Caused by: java.io.FileNotFoundException: /data/flink-1.15.4/ck/608fa9dfa369757dae033dc9053c12a9/shared/8e15b308-d076-4f64-88dd-0f9055a7062b (No such file or directory)
at java.base/java.io.FileInputStream.open0(Native Method)
at java.base/java.io.FileInputStream.open(Unknown Source)
at java.base/java.io.FileInputStream.(Unknown Source)
参考答案：
好像是跟状态有关系
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问题三：编译 flink-1.1.8源码报这个错，遇到过吗？
编译 flink-1.1.8源码报这个错，有大佬遇到过吗？
[ERROR] Failed to execute goal org.apache.maven.plugins:maven-shade-plugin:3.4.1:shade (shade-flink) on project flink-table-planner_2.12: Error creating shaded jar: Problem shading JAR /Users/fangwei/workspace/flink-sources/1.18/flink-release-1.18.0/flink-table/flink-table-planner/target/flink-table-planner_2.12-1.18.0.jar entry org/apache/calcite/sql/validate/SqlValidatorImpl$NavigationExpander.class: org.apache.maven.plugin.MojoExecutionException: Error in ASM processing class org/apache/calcite/sql/validate/SqlValidatorImpl$NavigationExpander.class: 19 -> [Help 1]
参考答案：
Error in ASM processing class，搜一下，很多说明
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问题四：按照flink官方文档写parquet报错怎么办？
按照flink官方文档写parquet报错？Exception in thread "main" java.io.UncheckedIOException: java.io.IOException: Serializing the source elements failed: java.lang.reflect.InaccessibleObjectException: Unable to make field private final java.lang.Object[] java.util.Arrays$ArrayList.a accessible: module java.base does not "opens java.util" to unnamed module @769a1df5
at org.apache.flink.streaming.api.functions.source.FromElementsFunction.setOutputType(FromElementsFunction.java:164)
at org.apache.flink.streaming.util.functions.StreamingFunctionUtils.trySetOutputType(StreamingFunctionUtils.java:84)
at org.apache.flink.streaming.util.functions.StreamingFunctionUtils.setOutputType(StreamingFunctionUtils.java:60)
at org.apache.flink.streaming.api.operators.AbstractUdfStreamOperator.setOutputType(AbstractUdfStreamOperator.java:147)
参考答案：
Java中的访问控制机制分为四个级别：private、default、protected和public。其中，private级别是最严格的，只有类自身才能访问这些字段。而其他类则无法直接访问或修改这些私有字段。
可以通过设置可访问性来解决java.lang.reflect.InaccessibleObjectException异常，但这并不是一个推荐的做法。毕竟，私有成员的存在是为了保护类的封装性和安全性。
——参考链接。
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