NullPointerException trying to handle an unannotated return type via contract-api

[davidkel]

Using 2.2.3LTS using the contract-api I have this method

   @Transaction(submit=false)
    public QueryResponse<String> paginatedRichQuery(Context ctx, String queryString, String pagesize, String passedBookmark) {
        logger.debug("Entering paginatedRichQuery with pagesize [" + pagesize + "] and query string: " + queryString);
        int pageSize = Integer.parseInt(pagesize);

        final QueryResultsIteratorWithMetadata<KeyValue> iterator = ctx.getStub().getQueryResultWithPagination(queryString, pageSize, passedBookmark);
        QueryResponseMetadata metadata = iterator.getMetadata();
        ArrayList<String> results = this.getAllResults(iterator);

        QueryResponse<String> response = new QueryResponse<String>(results.toArray(new String[results.size()]), new ResponseMetadata(metadata));
        logger.debug("Exiting paginatedRichQuery with response: " + response.toString());
        return response;
    }

QueryResponse is defined as follows

public class QueryResponse<T> {
    private T[] results;

    private ResponseMetadata responseMetadata;

    public QueryResponse(T[] results, ResponseMetadata responseMetadata) {
        this.results = results;
        this.responseMetadata = responseMetadata;
    }

    public T[] getResults() {
        return results;
    }

    public void setResults(T[] results) {
        this.results = results;
    }

    public ResponseMetadata getResponseMetadata() {
        return responseMetadata;
    }

    public void setResponseMetadata(ResponseMetadata responseMetadata) {
        this.responseMetadata = responseMetadata;
    }

}

When I invoke the transaction it fails due to trying because of the return value with

Thread[fabric-txinvoke:5,5,main] 12:04:38:330 INFO    org.hyperledger.fabric.contract.ContractRouter processRequest                    Got routing:paginatedRichQuery:org.example.FixedAssetContract
Thread[fabric-txinvoke:5,5,main] 12:04:38:345 SEVERE  org.hyperledger.fabric.Logger error                                              nulljava.lang.NullPointerException
        at org.hyperledger.fabric.contract.execution.JSONTransactionSerializer.toBuffer(JSONTransactionSerializer.java:84)
        at org.hyperledger.fabric.contract.execution.impl.ContractExecutionService.convertReturn(ContractExecutionService.java:89)
        at org.hyperledger.fabric.contract.execution.impl.ContractExecutionService.executeRequest(ContractExecutionService.java:67)
        at org.hyperledger.fabric.contract.ContractRouter.processRequest(ContractRouter.java:119)
        at org.hyperledger.fabric.contract.ContractRouter.invoke(ContractRouter.java:130)
        at org.hyperledger.fabric.shim.impl.ChaincodeInvocationTask.call(ChaincodeInvocationTask.java:100)
        at org.hyperledger.fabric.shim.impl.InvocationTaskManager.lambda$newTask$17(InvocationTaskManager.java:265)
        at java.base/java.util.concurrent.CompletableFuture$AsyncRun.run(CompletableFuture.java:1736)
        at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
        at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
        at java.base/java.lang.Thread.run(Thread.java:834)

[llkking]

also got this problem...actually peer returned the response but org.hyperledger.fabric.contract.execution.JSONTransactionSerializer.toBuffer(JSONTransactionSerializer.java:84) handle response happened a exception.i think maybe it's a bug

[llkking]

problem solved. cc method return value type should be defined by @datatype

[mbwhite]

Could certainly improve the error message here.