tools/release/java/readme.txt

# Copyright (C) 2016 and later: Unicode, Inc. and others.
# License & terms of use: http://www.unicode.org/copyright.html
# Copyright (C) 2009-2013 IBM and Others. All Rights Reserved

API Change Report:

A tool to generate a report of API status changes between two ICU4C releases.
(ICU4J has a builtin change report generator)

Requirements:
  - Everything needed to build ICU4C from a command line (UNIX) environment
  - Doxygen (for generating docs).
     Doxygen 1.8.13 or newer is recommended for ICU API docs,
     but an older Doxygen may work for the API Change Report.
  - Java JDK 1.8+
  - Apache Ant
  - Maven

To use the utility:
 1. Put both old and new ICU source trees on your system

2. Run "configure" in both old and new (you can use any mixture of in-source and out-of-source builds). Doxygen must be found during the configure phase, but you do not need to build the standard API docs.

3. create a Makefile.local in this readme's directory (tools/trunk/release/java/) 
            with just these two lines, for example:
			OLD_ICU=/xsrl/E/icu-6.7
			NEW_ICU=/xsrl/E/icu-6.8

           Set these paths to the location of parent directory of the
	   ICU4C sources in the previous version (OLD) and the
	   source of the current release (NEW)
	   
           If your ICU is an out-of-source-build, add these two lines
           indicating the build location:
                        OLD_ICU_BUILD=/xsrl/E/icu-build-m48
                        NEW_ICU_BUILD=/xsrl/E/icu-build

4. from this directory, (tools/release/java/) run Make to build docs: (the tool will be built automatically)
            make APIChangeReport.html
            make APIChangeReport.md

5. This will create 'APIChangeReport.html' and 'APIChangeReport.md" files in
this directory. Look them over, and then check them into ${NEW_ICU}/APIChangeReport.* (parent of icu4c's source).

Note: the ant build and makefile do not attempt to rebuild the jar. Run 'mvn package' separately if developing on the Java tool.