multiple method execution with same input processed

warm greetings.

I am having a scenario that i have 10 methods i.e. process1, process2..., process10
according to input i need to execute few methods out of 10 in specific order.
1)1,3,5,7
2)2,4,6,8
3)1,5,9,10

whatever order i am executing, output of 1st method should be used as the input of second method and so on.

i searched a lot in internet but didn't found anything suitable. I started doing below code.
as of now i am using concat method of java to achieve this.

public class Perform {
static String op = "";
public static void main(String[] args) {
process(list);
}
public static void process(List<String> list)
{
for(String str: list)
{
if(str.startsWith("Samsung"))
{
process1("test").concat(process2(op).concat(process3(op)).concat(process4(op)));
}
}
}
public static String process1(String str)
{
System.out.println("process1 start");
System.out.println("str1:"+str);
System.out.println("process1 end");
return str+"1";
}
public static String process2(String str)
{
System.out.println("process2 start");
System.out.println("str2:"+str);
System.out.println("process2 end");
return str+"2";
}
public static String process3(String str)
{
System.out.println("process3 start");
System.out.println("str3:"+str);
System.out.println("process3 end");
return str+"3";
}
public static String process4(String str)
{
System.out.println("process4 start");
System.out.println("str4:"+str);
System.out.println("process4 end");
return str+"4";
}
}

output :

process1 start

str1:test

process1 end

process2 start

str2:

op :

process2 end

process3 start

str3:

process3 end

process4 start

str4:

process4 end

op:test1234

the answer is expected and processing all 4 methods but the issue is : it is not printing the value of "str" which is the parameter. why ?

if i am keeping the code

op = process1("test");
op = process2(op);
op = process3(op);
op = process4(op);

in place of

process1("test").concat(process2(op).concat(process3(op)).concat(process4(op)));

then it is printing the value of str which is an parameter.

Please answer the question from below code as well as suggest me some good code for this scenario.

I have found the solution. I developed below code to solve it. Please let me know if anybody is having a better solution for this.

public class Perform {
private static List<Integer> SamsungMethodExecution = Arrays.asList(1,3,5,7);
private static List<Integer> NokiaMethodExecution = Arrays.asList(2,4,6,8);
private static List<Integer> LgMethodExecution = Arrays.asList(1,5,9,10);
public static void main(String[] args) {
List<String> list = new ArrayList<>();
list.add("Lgmsg");
list.add("Samsungmsg");
list.add("Nokiamsg");
list.add("Lgmsg");
list.add("Samsungmsg");
list.add("Nokiamsg");
list.add("Lgmsg");
list.add("Samsungmsg");
list.add("Nokiamsg");
//		
process(list);
}
public static void process(List<String> list)
{
for(String str: list)
{
if(str.startsWith("Samsung"))
{
System.out.println("SAMSUNG======================================");
Process.process(SamsungMethodExecution, str.replace("Samsung", ""));
System.out.println("SAMSUNG======================================");
System.out.println();
}else if(str.startsWith("Nokia"))
{
System.out.println("NOKIA========================================");
Process.process(NokiaMethodExecution, str.replace("Nokia", ""));
System.out.println("NOKIA========================================");
System.out.println();
}else
{
System.out.println("LG===========================================");
Process.process(LgMethodExecution, str.replace("Lg", ""));
System.out.println("LG===========================================");
System.out.println();
}
}
}
public class Process {
public static String process(List<Integer> processList, String msg) {
String output = "";
for(int i: processList)
{
switch(i)
{
case 1:
output = Process.process1(msg); break;
case 2:
output = Process.process2(msg); break;
case 3:
output = Process.process3(msg); break;
case 4:
output = Process.process4(msg); break;
case 5:
output = Process.process5(msg); break;
case 6:
output = Process.process6(msg); break;
case 7:
output = Process.process7(msg); break;
case 8:
output = Process.process8(msg); break;
case 9:
output = Process.process9(msg); break;
case 10:
output = Process.process10(msg); break;
default :
System.out.println("Sorry, no specific match found");
}
}
return output;
}
public static String process1(String msg)
{
System.out.println("process1: "+msg);
return msg;
}
public static String process2(String msg)
{
System.out.println("process2: "+msg);
return msg;
}
public static String process3(String msg)
{
System.out.println("process3: "+msg);
return msg;
}
public static String process4(String msg)
{
System.out.println("process4: "+msg);
return msg;
}
public static String process5(String msg)
{
System.out.println("process5: "+msg);
return msg;
}
public static String process6(String msg)
{
System.out.println("process6: "+msg);
return msg;
}
public static String process7(String msg)
{
System.out.println("process7: "+msg);
return msg;
}
public static String process8(String msg)
{
System.out.println("process8: "+msg);
return msg;
}
public static String process9(String msg)
{
System.out.println("process9: "+msg);
return msg;
}
public static String process10(String msg)
{
System.out.println("process10: "+msg);
return msg;
}
}

Two classes one is main class and another is Process class which is having a actual logic.