Batch.java

@RestResource(urlMapping='/dedup/*')
global with sharing class AAA_DEDUP{
   @HttpPost
   global static List<Contact> findContacts(List<Contact> cons) {
   
        List<Contact> cons1 = new List<Contact>();
        List<Contact> cons2 = new List<Contact>();
        List<Contact> cons3 = new List<Contact>();
        List<Contact> cons4 = new List<Contact>();
        List<Contact> cons5 = new List<Contact>();
        
        List<Contact> foundContacts = new List<Contact>();
        List<Datacloud.FindDuplicatesResult> results1;
        List<Datacloud.FindDuplicatesResult> results2;
        List<Datacloud.FindDuplicatesResult> results3;
        List<Datacloud.FindDuplicatesResult> results4;
        List<Datacloud.FindDuplicatesResult> results5;
        
        for(Integer i = 0; i < cons.size(); i++){
            if(cons[i] != null){
                if(i<50){
                    cons1.add(cons[i]);
                }
                if(i>=50 && i<100){
            
                    cons2.add(cons[i]);
                }
                if(i>=100 && i<150){
            
                    cons3.add(cons[i]);
                }
                if(i>=150 && i<200){
            
                    cons4.add(cons[i]);
                }
                if(i>=200 && i<250){
            
                    cons5.add(cons[i]);
                }
            }
        }

        try {
            results1 = Datacloud.FindDuplicates.findDuplicates(cons1);
            results2 = Datacloud.FindDuplicates.findDuplicates(cons2);
            results3 = Datacloud.FindDuplicates.findDuplicates(cons3);
            results4 = Datacloud.FindDuplicates.findDuplicates(cons4);
            results5 = Datacloud.FindDuplicates.findDuplicates(cons5);
        } catch (Exception ex) {
            return null;
        }
    
        // Loop the original cons
        for (Integer i = 0; i < cons1.size(); i++) {
            Contact foundCon = null;
            // Find the first duplicate result with a match result, then use the first match record.
            for (Datacloud.DuplicateResult dr : results1[i].getDuplicateResults()) {
                if (dr.matchResults.size() > 0 && dr.getMatchResults()[0].matchRecords.size() > 0) {
                    foundCon = (Contact) dr.getMatchResults()[0].getMatchRecords()[0].getRecord();
                    break;
                }
            }
            foundContacts.add(foundCon);
        }
        
         for (Integer i = 0; i < cons2.size(); i++) {
            Contact foundCon = null;
            // Find the first duplicate result with a match result, then use the first match record.
            for (Datacloud.DuplicateResult dr : results2[i].getDuplicateResults()) {
                if (dr.matchResults.size() > 0 && dr.getMatchResults()[0].matchRecords.size() > 0) {
                    foundCon = (Contact) dr.getMatchResults()[0].getMatchRecords()[0].getRecord();
                    break;
                }
            }
            foundContacts.add(foundCon);
        }
        
         for (Integer i = 0; i < cons3.size(); i++) {
            Contact foundCon = null;
            // Find the first duplicate result with a match result, then use the first match record.
            for (Datacloud.DuplicateResult dr : results3[i].getDuplicateResults()) {
                if (dr.matchResults.size() > 0 && dr.getMatchResults()[0].matchRecords.size() > 0) {
                    foundCon = (Contact) dr.getMatchResults()[0].getMatchRecords()[0].getRecord();
                    break;
                }
            }
            foundContacts.add(foundCon);
        }
        
         for (Integer i = 0; i < cons4.size(); i++) {
            Contact foundCon = null;
            // Find the first duplicate result with a match result, then use the first match record.
            for (Datacloud.DuplicateResult dr : results4[i].getDuplicateResults()) {
                if (dr.matchResults.size() > 0 && dr.getMatchResults()[0].matchRecords.size() > 0) {
                    foundCon = (Contact) dr.getMatchResults()[0].getMatchRecords()[0].getRecord();
                    break;
                }
            }
            foundContacts.add(foundCon);
        }
        
         for (Integer i = 0; i < cons5.size(); i++) {
            Contact foundCon = null;
            // Find the first duplicate result with a match result, then use the first match record.
            for (Datacloud.DuplicateResult dr : results5[i].getDuplicateResults()) {
                if (dr.matchResults.size() > 0 && dr.getMatchResults()[0].matchRecords.size() > 0) {
                    foundCon = (Contact) dr.getMatchResults()[0].getMatchRecords()[0].getRecord();
                    break;
                }
            }
            foundContacts.add(foundCon);
        }
        
        
        
        return foundContacts;
    }

}