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Template Method Design Pattern in Java

Learn Template Method Design Pattern in Java with workflow standardization, Spring JdbcTemplate, batch processing, enterprise frameworks, UML diagrams, Java implementation, and real-world examples.

What You Will Learn

  • What is Template Method Pattern?
  • Why Template Method Pattern is Needed
  • Workflow Standardization
  • Java Implementation
  • Spring JdbcTemplate Example
  • Batch Processing Example
  • Enterprise Use Cases
  • Benefits and Limitations
  • Interview Questions

Introduction

Many enterprise applications follow the same workflow but differ in certain steps.

Examples:

Process Payment

Validate Request

Execute Payment

Send Notification

Different payment methods:

Credit Card

PayPal

UPI

The workflow is same.

Only implementation changes.

Without Template Method:

if(type.equals("CARD")) {
   validate();
   processCard();
   notifyUser();
}
else if(type.equals("UPI")) {
   validate();
   processUpi();
   notifyUser();
}

Code duplication increases.

Template Method solves this problem.

What is Template Method Pattern?

Template Method is a Behavioral Design Pattern that defines the skeleton of an algorithm in a base class while allowing subclasses to implement specific steps.

Simple View:

Common Workflow

↓

Fixed Steps

↓

Custom Implementation

Purpose of Template Method

Primary Goal:

Reuse Common Workflow

While Allowing

Custom Behavior

Real World Analogy

Making Coffee and Tea.

Steps:

Boil Water

Add Main Ingredient

Pour Into Cup

Serve

Coffee:

Add Coffee Powder

Tea:

Add Tea Leaves

Workflow is same.

Implementation differs.

Problem Without Template Method

flowchart LR
    A[Coffee Logic]
    B[Tea Logic]
    C[Milk Logic]

    A --> B
    B --> C

Repeated workflow logic.

Hard maintenance.

Solution With Template Method

flowchart LR
    A[Abstract Workflow]
    B[Coffee]
    C[Tea]
    D[Milk]

    A --> B
    A --> C
    A --> D

Shared workflow.

Custom implementation.

Template Method Architecture

flowchart LR
    A[Abstract Class]
    B[Template Method]
    C[Concrete Class A]
    D[Concrete Class B]

    A --> B
    A --> C
    A --> D

Key Components

Abstract Class

Defines workflow.

Template Method

Defines fixed sequence of operations.

Concrete Class

Implements variable steps.

UML Diagram

classDiagram

class PaymentProcessor {
    +processPayment()
    +validate()
    +executePayment()
    +sendNotification()
}

class CreditCardProcessor
class UpiProcessor

PaymentProcessor <|-- CreditCardProcessor
PaymentProcessor <|-- UpiProcessor

Payment Processing Example

Workflow:

Validate

Process Payment

Generate Receipt

Send Notification

Every payment type follows this flow.

Step 1: Abstract Class

public abstract class PaymentProcessor {

    public final void processPayment() {

        validate();

        executePayment();

        generateReceipt();

        sendNotification();
    }

    protected abstract void validate();

    protected abstract void executePayment();

    protected void generateReceipt() {

        System.out.println(
                "Receipt Generated");
    }

    protected void sendNotification() {

        System.out.println(
                "Notification Sent");
    }
}

Step 2: Credit Card Processor

public class CreditCardProcessor
        extends PaymentProcessor {

    @Override
    protected void validate() {

        System.out.println(
                "Validating Card");
    }

    @Override
    protected void executePayment() {

        System.out.println(
                "Processing Card Payment");
    }
}

Step 3: UPI Processor

public class UpiProcessor
        extends PaymentProcessor {

    @Override
    protected void validate() {

        System.out.println(
                "Validating UPI");
    }

    @Override
    protected void executePayment() {

        System.out.println(
                "Processing UPI Payment");
    }
}

Step 4: Client

public class TemplateDemo {

    public static void main(
            String[] args) {

        PaymentProcessor processor =
                new CreditCardProcessor();

        processor.processPayment();
    }
}

Output

Validating Card

Processing Card Payment

Receipt Generated

Notification Sent

Execution Flow

flowchart LR
    A[Validate]
    B[Process Payment]
    C[Generate Receipt]
    D[Send Notification]

    A --> B
    B --> C
    C --> D

Hook Methods

Template Method supports optional steps.

Example:

protected boolean shouldNotify() {

    return true;
}

Template:

if(shouldNotify()) {

    sendNotification();
}

Hook Flow

flowchart LR
    A[Process Payment]
    B[Check Hook]
    C[Send Notification]

    A --> B
    B --> C

Banking Example

Loan Processing Workflow:

Validate Application

Credit Check

Approval Decision

Disbursement

Different loan types:

Home Loan

Car Loan

Personal Loan

Use same workflow.

Banking Workflow

flowchart LR
    A[Validation]
    B[Credit Check]
    C[Approval]
    D[Disbursement]

    A --> B
    B --> C
    C --> D

Insurance Example

Claim Processing:

Validate Claim

Verify Documents

Fraud Check

Approve Claim

Insurance Workflow

flowchart LR
    A[Validate Claim]
    B[Document Check]
    C[Fraud Check]
    D[Approval]

    A --> B
    B --> C
    C --> D

Spring JdbcTemplate Example

One of the best real-world examples.

Without JdbcTemplate:

Open Connection

Create Statement

Execute Query

Process Result

Close Connection

Repeated everywhere.

JdbcTemplate Handles

jdbcTemplate.query(
        sql,
        rowMapper);

Framework manages:

Connection

Statement

Exception Handling

Resource Cleanup

Developer provides:

RowMapper

Only variable part.

JdbcTemplate Flow

flowchart LR
    A[Open Connection]
    B[Execute Query]
    C[Row Mapper]
    D[Close Connection]

    A --> B
    B --> C
    C --> D

Spring Batch Example

Batch Workflow:

Read

Process

Write

Same structure.

Different implementations.

Spring Batch Flow

flowchart LR
    A[Reader]
    B[Processor]
    C[Writer]

    A --> B
    B --> C

Enterprise Examples

Banking

Loan Processing

Account Opening

KYC Verification

Insurance

Claim Processing

Policy Approval

Retail

Order Processing

Shipment Processing

Healthcare

Patient Registration

Treatment Workflow

Framework Examples

Common Template Method implementations:

Spring JdbcTemplate

RestTemplate

RedisTemplate

KafkaTemplate

Hibernate Template

Benefits

✅ Eliminates Code Duplication

✅ Reuses Common Workflow

✅ Supports Open Closed Principle

✅ Easier Maintenance

✅ Consistent Processing Logic

✅ Framework Friendly

Limitations

❌ Uses Inheritance

❌ Deep Hierarchies Can Become Complex

❌ Less Flexible Than Composition

When To Use

Use Template Method when:

  • Workflow is fixed
  • Only a few steps vary
  • Code duplication exists
  • Multiple implementations share same process

When Not To Use

Avoid when:

  • Entire algorithm changes
  • Runtime switching is required

Use Strategy Pattern instead.

Template Method vs Strategy

Feature Template Method Strategy
Uses Inheritance Composition
Runtime Change No Yes
Flexibility Medium High
Workflow Fixed Dynamic

Template Method vs Factory Method

Feature Template Method Factory Method
Focus Algorithm Workflow Object Creation
Type Behavioral Creational
Purpose Process Reuse Object Instantiation

Real Enterprise Architecture

flowchart LR
    A[Application]
    B[Template Workflow]
    C[Custom Step]
    D[Business Logic]

    A --> B
    B --> C
    C --> D

Interview Questions

What is Template Method Pattern?

A behavioral pattern that defines the skeleton of an algorithm and allows subclasses to implement specific steps.

Main Components?

Abstract Class

Template Method

Concrete Class

Why is Template Method Useful?

It removes duplicate workflow code.

Real Spring Example?

JdbcTemplate

RestTemplate

RedisTemplate

KafkaTemplate

Difference Between Strategy and Template Method?

Strategy uses composition and supports runtime switching.

Template Method uses inheritance and defines fixed workflows.

Key Takeaways

  • Template Method is a Behavioral Design Pattern.
  • Defines workflow skeleton in a base class.
  • Allows subclasses to customize certain steps.
  • Eliminates duplicate code.
  • Widely used in Spring Framework templates.
  • Great for workflow-driven enterprise systems.
  • Common in Banking, Insurance, Retail, and Batch Processing systems.