Java & JVM in 2025: The Complete Guide

Japanese Edition
https://daisuke.masuda.tokyo/article-2025-11-14-0352

This presentation provides a comprehensive overview of Java and JVM ecosystem trends in 2025. From the latest Java 23 features (Virtual Threads, GraalVM native-image) to language evolution history, reasons for choosing Java/Kotlin for server-side development, and detailed performance and feature comparisons with other languages (Go, Python, TypeScript), we conduct technical deep dives. Additionally, we present real market data on Java engineer demand and compensation both in Japan (¥6M-14M annually) and globally ($95K-170K+ annually), along with future trends and recommendations that reveal the complete picture of the Java ecosystem.

Transcript

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7.  Java & JVM Benchmarks across various workloads show against other popular languages. Modern JVM optimizations, JIT compilation, and mature GC algorithms deliver high throughput for backend services. Generally comparable performance (±10%) with Go sometimes edging ahead in memory efficiency and startup times, Java excelling in long-running workloads after JIT warm-up. Java typically 20-40% faster for CPU- bound tasks, though Node excels in I/O-heavy workloads leveraging its event loop architecture. Java performs 4-10x faster depending on workload. Python's GIL limits parallel execution and requires C extensions for intensive computations. November 2025
8.  ⚠ While Java/JVM offers numerous advantages, it's important to recognize its limitations and challenges. Let's explore the first two major drawbacks and their practical solutions in modern Java development. November 2025 Java is more verbose than modern alternatives like Python or Go, requiring more code for equivalent functionality. This can slow development velocity and increase maintenance overhead. Records (Java 16+), pattern matching, Lombok libraries, or migrating to Kotlin can significantly reduce boilerplate and improve readability while maintaining JVM compatibility and type safety benefits. Traditional JVM applications consume significant memory (larger heap sizes) and have slower startup times compared to native applications, which can impact microservices deployment density and serverless function cold starts. Class Data Sharing (CDS), AppCDS, GraalVM native-image AOT compilation, and modern frameworks like Quarkus and Micronaut that specifically optimize for cloud-native environments with faster startup and lower memory profiles.  Java & JVM
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