Introduction

The transition from Spring Boot 1.3.7.RELEASE to 1.4.1.RELEASE can often introduce compatibility issues and deprecated methods that developers must address to ensure a seamless upgrade. One such issue that may arise is the java.lang.NoSuchMethodError related to the SpringApplicationBuilder.showBanner method. This article explores the technical root cause of this issue, provides practical solutions, and summarizes key changes between these versions to facilitate a smoother transition.

Understanding java.lang.NoSuchMethodError

java.lang.NoSuchMethodError is a runtime error that occurs when a particular method is called on a class, but the method definition cannot be found. This typically happens when there is a version mismatch between the libraries, leading to differences in the API's available methods. In the context of Spring Boot, this usually results from using an older API with a newer version of the Spring framework where certain methods may have been removed or changed.

Overview of the SpringApplicationBuilder.showBanner

Issue

In versions prior to Spring Boot 1.4, SpringApplicationBuilder provided a method showBanner(boolean) to control the display of the startup banner. With the release of Spring Boot 1.4, this method was removed, and its functionality was replaced with a more extensible mechanism using Banner.Mode .

Key Changes in Spring Boot 1.4

1. Deprecation and Removal: The showBanner(boolean) method was removed in favor of a more flexible mechanism.
2. **Introduction of Banner.Mode **: Developers can choose from Banner.Mode.OFF , Banner.Mode.CONSOLE , and Banner.Mode.LOG to control how the banner is displayed.

Practical Solution

To address the NoSuchMethodError , you must update the code that previously used showBanner() to the new API:

Old Implementation:

• Review Version Release Notes: Always review the release notes and migration guides provided by Spring Boot for any deprecated APIs and their alternatives.
• Update Dependencies: Ensure that all dependencies are compatible with Spring Boot 1.4. Update libraries and tools to their latest versions where necessary.
• Test Thoroughly: Implement comprehensive testing to catch any unforeseen issues resulting from the update, especially if you have custom startup logic.