The following code creates 100 data records with sequential partition keys and puts them in a stream called DataStream.

AmazonKinesisClient amazonKinesisClient = new AmazonKinesisClient(credentialsProvider);
PutRecordsRequest putRecordsRequest  = new PutRecordsRequest();
putRecordsRequest.setStreamName("DataStream");
List <PutRecordsRequestEntry> putRecordsRequestEntryList  = new ArrayList<>(); 
for (int i = 0; i < 100; i++) {
    PutRecordsRequestEntry putRecordsRequestEntry  = new PutRecordsRequestEntry();
    putRecordsRequestEntry.setData(ByteBuffer.wrap(String.valueOf(i).getBytes()));
    putRecordsRequestEntry.setPartitionKey(String.format("partitionKey-%d", i));
    putRecordsRequestEntryList.add(putRecordsRequestEntry); 
}

putRecordsRequest.setRecords(putRecordsRequestEntryList);
PutRecordsResult putRecordsResult  = amazonKinesisClient.putRecords(putRecordsRequest);
System.out.println("Put Result" + putRecordsResult);