NPE in zookeeperdiscoveryclient when instance-port not specified

I am seeing a strange NPE in ZKDC when the client is accessed first time to load the list of service instances:

java.lang.NullPointerException: null
	at org.springframework.cloud.zookeeper.discovery.ZookeeperDiscoveryClient.getInstances(ZookeeperDiscoveryClient.java:89)

It seems that under certain conditions, ZookeeperServiceDiscovery.build() is never called - and the bulk of init work is being done there. After adding the property spring.cloud.zookeeper.discovery.instance-port the npe went away. The instance-port property is optional though, it should default to the listen port.

Note that the only other zookeeper related property i am using is spring.cloud.zookeeper.connect-string

[jorgheymans]

Version 1.0.3, the only config property I had defined was the zookeeper connection string.

[lurongjiang]

@spencergibb Thanks.I found out why it didn’t work in my project.I debugger and get the byte for path from curator client,the data:

{
  "payload": {
    "@class": "org.springframework.cloud.zookeeper.discovery.ZookeeperInstance",
    "metadata": {
      "groupId": "WGQ",
      "role": "TestApp-LRJ",
      "instance_status": "UP"
    },
    "name": "TestApp",
    "id": "TestApp-1"
  },
  "registrationTimeUTC": 1635852567130,
  "serviceType": "DYNAMIC",
  "sslPort": null,
  "uriSpec": {
    "parts": [
      {
        "variable": true,
        "value": "scheme"
      },
      {
        "variable": false,
        "value": "://"
      },
      {
        "variable": true,
        "value": "address"
      },
      {
        "variable": false,
        "value": ":"
      },
      {
        "variable": true,
        "value": "port"
      }
    ]
  },
  "address": "localhost",
  "name": "TestApp",
  "id": "TestApp-1",
  "port": 8086
}

then I tried to deserialize the data to ZookeeperInstance,the code

public class TestDeserialize {
    public static void main(String[] args) throws Exception {
        Path path = Paths.get(args[0]);
        byte[] bytes = Files.readAllBytes(path);
        JsonInstanceSerializer<ZookeeperInstance> serializer = new JsonInstanceSerializer<>(ZookeeperInstance.class);
        ServiceInstance<ZookeeperInstance> instanceServiceInstance = serializer.deserialize(bytes);
        System.out.println(instanceServiceInstance.getName());
    }
}

then I got the json string

{"name":"","id":"","address":null,"port":null,"sslPort":null,"payload":null,"registrationTimeUTC":0,"serviceType":"DYNAMIC","uriSpec":null,"enabled":true}

then I found the ObejctMapper was from org.codehaus.jackson:jackson-mapper-asl:1.8.8.

I realized that it might be a dependency omit problem.I exclude the jackson from hadoop, then it work

<dependency>
    <groupId>org.apache.hadoop</groupId>
    <artifactId>hadoop-yarn-client</artifactId>
    <exclusions>
        <exclusion>
            <groupId>org.codehaus.jackson</groupId>
            <artifactId>*</artifactId>
        </exclusion>
    </exclusions>
</dependency>

It just was a bug in my code.Thank for your reply.