simply about difficult
You may encounter an exception like this: Most likely, you have a versioning problem: you are using hbase-client version 2.x.x with the server version 1.x.x. Also, you are trying to call HBase Admin API functions. The fact is that the hbase-client version 2.x.x can send only regular get, scan, put, delete requests to the hbase […]
READ MOREWhen using gRPC streaming or in some other cases, it may be necessary to compose one complete object from several others or from an iterator. Let’s take a look at an example. We have an iterator, received by gRPC stub: And we want to get one complete ProtoResult object, which will be the union of all […]
READ MOREIf you are looking for default scan request parameters, here they are: Parameter Default value startRow HConstants.EMPTY_START_ROW stopRow HConstants.EMPTY_END_ROW maxVersions 1 batch -1 allowPartialResults false storeLimit -1 storeOffset 0 caching -1 maxResultSize -1L cacheBlocks true reversed false timeRange TimeRange.allTime() asyncPrefetch null small false mvccReadPoint -1L limit -1 readType Scan.ReadType.DEFAULT needCursorResult false
READ MOREWhen checking the quality of the code, you may encounter a problem that sounds like this: Or like this: This is not a bug in PMD. Here are some examples:
READ MORELet’s say you need to get the name of hdfs cluster in an application. To do this, you need to get the org.apache.hadoop.conf.Configuration object: In the place we need, we get the fs.defaultFS property value:
READ MORELet’s say we need to terminate Spring Boot Yarn application due to checked exception. To do this, in the AppMaster class (it must be specified in the appmaster-class property in application.yml) we need to call the method in the place we need: If you need to stop the application from outside the AppMaster class, you can […]
READ MORELet’s imagine that we have a task: And the code for its execution: And we need to get the return value after completing the task. For this, Runnable must be replaced with Callable: And when sending a task to an ExecutorService, you need to use submit method instead of execute, and capture a Future<Object> object:
READ MORELet’s imagine we have a gRPC service: We are writing a unit test or integration test, and we need to make a test stub for this service. Let’s use Mockito. The code we write below can be used in any way. You can even use it in pure Java. Let’s connect the dependencies to the project: Now, let’s mock […]
READ MOREThe error looks like this: To solve the problem, you need to update the bytebuddy version to 1.9.3: If the version update did not fix the error, you need to find the correct version of the dependency. Instructions are here: https://mchesnavsky.tech/determine-versions-of-dependencies-of-library-maven/
READ MOREImagine you need to determine the version of Apache commons-lang dependency in ZooKeeper 3.6.2. The easiest way to do this is to find the artifact page in the mvn repository. For ZooKeeper 3.6.2: https://mvnrepository.com/artifact/org.apache.zookeeper/zookeeper/3.6.2. On the page, you need to find the Compile Dependencies section, and find the required dependency there. In our case, the commons-lang 2.6 dependency […]
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