Java is the most common destination for enterprise COBOL migration, and it is easy to see why. It is mature, strongly typed, backed by an enormous library ecosystem, and supported by one of the deepest developer hiring pools in the UK. For organisations running critical COBOL on IBM mainframes, Java offers a route to a modern platform without abandoning the enterprise-grade rigour those systems demand.
This guide explains what a COBOL to Java migration actually involves, the approaches available to UK enterprises, what it costs, and how to manage the risk.
TL;DR
Java is the default COBOL migration target for large enterprises because of its mature ecosystem, strong typing, and vast developer pool
Financial precision is non-negotiable: COBOL packed-decimal (COMP-3) fields must map to Java BigDecimal, never double or float
