System.LimitException: Apex CPU time limit exceeded

The Apex CPU time limit exceeded error is a standard Salesforce error which occurs when the salesforce governor limit to run the Apex code has exceeded.The maximum CPU time to run the Apex code on the Salesforce servers is:

• ​10,000 milliseconds (Synchronous limit)  
• 60,000 milliseconds (Asynchronous limit)

below are the methods where we can get the CPU time and CPU limit.

Limits.getCPUTime() - Returns the CPU time(in milliseconds) accumulated on the salesforce.com server in the current transaction.

Limits.getLimitCPUTime() - Returns the total CPU time (in milliseconds) accumulated on the salesforce.com servers in the current transaction.


Example :

 Below code error is coming due to FOR inside FOR loop.
Set<String> setDependantValue = new Set<String>();
        for(Payment_Process__c objPicklistValues : lstProduct_Line){
            setDependantValue.add(objPicklistValues.Payment_Name__c);
        }
        Map<String, List<String>> mapDependantControllingValue = new Map<String, List<String>>();
        for(String objDepVal : setDependantValue){
            List<String> lstControllingValues = new List<String>();
            for(Payment_Process__c objPicklistValues : lstProduct_Line){
                if(objDepVal == objPicklistValues.Payment_Name__c){
                    lstControllingValues.add(objPicklistValues.Product_Family_Name__c);
                }
            }
            mapDependantControllingValue.put(objDepVal, lstControllingValues);
        } 

Solution : 
 Issue is resolved by following optimized code.
 Map<String, List<String>> mapDepValContVal = new Map<String, List<String>>();
        for(Payment_Process__c prdLine : lstProduct_Line){
            List<String> lstControllingValues = mapDepValContVal.get(prdLine.Line__c);
            if(lstControllingValues == null)
                lstControllingValues = new list<String>();
            lstControllingValues.add(prdLine.Family__c);
            mapDepValContVal.put(prdLine.Line__c, lstControllingValues);
        }