Java split not working as expected for string “--”

Question

I am trying to break a paragraph based on the string "--" in a complete line and the paragraph looks like below. i have to break if a line contains only "--" only i cannot split based on line as i have some other limitation.

Hi Hello this is -- to test

--

java split function -- test

Expected output.

["Hi Hello this is -- to test", "java split function -- test"]

i tried the below code and it did not work

searchValue.split("--")

and

searchValue.split("\n--\n")

both of them have not worked. and is splitting for all "--" in a line

any idea how i should write the split in this case

Exact input string:

start_check_state.log-
start_check_state.log-Initializing WebLogic Scripting Tool (WLST) ...
start_check_state.log-
start_check_state.log:Welcome to WebLogic Server Administration Scripting Shell 
start_check_state.log-
start_check_state.log-Type help() for help on available commands
start_check_state.log-
start_check_state.log-Connecting to t3://0.0.0.0:6300 with userid system ...
start_check_state.log-Successfully connected to Admin Server '' that belongs to domain 'dev'.
--
cia.log.2017-07-20-10.07.2017 6:00:05.963 [INFO ] <CIA> - <session.CIADispatcherBean> - <Flow_Id Alarm_Id/NC_Id : JOB PROCESS> <EventType : Activate Maintenance Ticket> - [event :alarmKey=JOB PROCESS,srcSystem=CIA Planned Maintenance]
cia.log.2017-07-20-10.07.2017 6:00:05.965 [INFO ] <CIA> - <em.CIAEventQueue> - <Flow_Id Alarm_Id/NC_Id : JOB PROCESS> <EventType : Activate Maintenance Ticket> - COMPLETED
cia.log.2017-07-20-10.07.2017 6:00:06.039 [INFO ] <CIA> - <messagelisteners.MessageListenerDelegate> - <Flow_Id Alarm_Id/NC_Id : JOB PROCESS> <EventType : Close Maintenance Ticket> - message handling started. sequence = [-1115362510203642553] node = 
cia.log.2017-07-20-10.07.2017 6:00:06.040 [INFO ] <CIA> - <dispatcher.MDBProcessor> - <Flow_Id Alarm_Id/NC_Id : JOB PROCESS> <EventType : Close Maintenance Ticket> - CIA Event <JOB PROCESS> processing on <>
cia.log.2017-07-20-10.07.2017 6:00:06.043 [INFO ] <CIA> - <dispatcher.MDBProcessor> - <Flow_Id Alarm_Id/NC_Id : JOB PROCESS> <EventType : Close Maintenance Ticket> - CIA Event <JOB PROCESS> was successfully processed on <>
cia.log.2017-07-20:10.07.2017 6:00:06.044 [INFO ] <CIA> - <messagelisteners.MessageListenerDelegate> - <Flow_Id Alarm_Id/NC_Id : JOB PROCESS> <EventType : Close Maintenance Ticket> - message processed. sequence = [-1115362510203642553] node =  
cia.log.2017-07-20-10.07.2017 6:00:06.058 [INFO ] <CIA> - <messagelisteners.MessageListenerDelegate> - <Flow_Id Alarm_Id/NC_Id : JOB PROCESS> <EventType : Activate Maintenance Ticket> - message handling started. sequence = [-1115362510203642553] node = test123
cia.log.2017-07-20-10.07.2017 6:00:06.060 [INFO ] <CIA> - <dispatcher.MDBProcessor> - <Flow_Id Alarm_Id/NC_Id : JOB PROCESS> <EventType : Activate Maintenance Ticket> - CIA Event <JOB PROCESS> processing on <>
cia.log.2017-07-20-10.07.2017 6:00:06.063 [INFO ] <CIA> - <dispatcher.MDBProcessor> - <Flow_Id Alarm_Id/NC_Id : JOB PROCESS> <EventType : Activate Maintenance Ticket> - CIA Event <JOB PROCESS> was successfully processed on <>
cia.log.2017-07-20-10.07.2017 6:00:06.064 [INFO ] <CIA> - <messagelisteners.MessageListenerDelegate> - <Flow_Id Alarm_Id/NC_Id : JOB PROCESS> <EventType : Activate Maintenance Ticket> - message processed. sequence = [-1115362510203642553] node = 
--
cpm_.log-2017-07-10 05:27:53 INFO  com..solutions.tfnurg.toms.cpm.job.BorrowedEquipmentNotificationJob :29 - Job for creating notification tasks started.
cpm_.log-2017-07-10 05:27:53 INFO  com..solutions.tfnurg.toms.cpm.bean.impl.test123 :471 - All required remind tasks created without any errors
cpm_.log:2017-07-10 05:27:53 INFO  com..solutions.tfnurg.toms.cpm.job.BorrowedEquipmentNotificationJob :46 - Created Notification Tasks: 
cpm_.log-2017-07-10 05:27:53 INFO  com..solutions.tfnurg.toms.cpm.job.BorrowedEquipmentNotificationJob :34 - Job for creating notification tasks ended.
--

Answer 1

You should search for both \\n (newline) and/or \\r (carriage return).

Try this regex:

[\n\r]+--[\n\r]+

DEMO: https://regex101.com/r/huPete/1

In Java:

searchValue.split("[\\n\\r]+--[\\n\\r]+")

Answer 2

This works fine for me, perhaps there is strange whitespace as suggested by the other answers & comments.

Here's a demo showing the input and output you hoped for: https://ideone.com/1vKnrm

Input:

import java.util.Arrays;

/**
 * https://stackoverflow.com/questions/45276416/java-split-not-working-as-expected-for-string
 */
class JavaSplitTest
{
  public static void main(String[] args)
  {
    String searchValue = "Hi Hello this is -- to test\n" +
      "\n" +
      "--\n" +
      "\n" +
      "java split function -- test\n";

    String[] splitted = searchValue.split("\n--\n");

    System.out.println(Arrays.asList(splitted));
  }
}

Output:

[Hi Hello this is -- to test
, 
java split function -- test
]