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Source: Apache Ant

Apache Ant is a software tool for automating software build processes for Java applications which originated from the Apache Tomcat project in early 2000 as a replacement for the Make build tool of Unix. It is similar to Make, but is implemented using the Java language and requires the Java platform. Unlike Make, which uses the Makefile format, Ant uses XML to describe the code build process and its dependencies.
Released under an Apache License by the Apache Software Foundation, Ant is an open-source project.

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and tasks to set up the command lines, and handle all the details of mapping from information in the build file to the program's arguments and interpreting the return value. Users can see which tasks do this (e.g. , , , ), by trying to execute the task on a system without the underlying program on the path, or without a full Java Development Kit (JDK) installed.

Portability

Ant is intended to work with all systems for which Java runtimes are available. It is most commonly used with Windows, Linux, macOS and other Unix operating systems but has also been used on other platforms such as OS/2, OpenVMS, Solaris, HP-UX.
Ant was designed to be more portable than Make. Compared to Make, Ant uses less platform-specific shell commands. Ant provides built-in functionality that is designed to behave the same on all platforms. For example, in the sample build.xml file above, the clean target deletes the classes directory and everything in it. In a Makefile this would typically be done with the command:

rm -rf classes/

rm is a Unix-specific command unavailable in some other environments. Microsoft Windows, for example, would use:

rmdir /S /Q classes

In an Ant build file the same goal would be accomplished using a built-in command:

Additionally, Ant does not differentiate between forward slash or backslash for directories and semicolon or colon for path separators. It converts each to the symbol appropriate to the platform on which it executes.

Limitations

Ant build files, which are written in XML, can be complex and verbose, as they are hierarchical, partly ordered, and pervasively cross-linked. This complexity can be a barrier to learning. The build files of large or complex projects can become unmanageably large. Good design and modularization of build files can improve readability but not necessarily reduce size.
Many of the older tasks, such as , and —use default values for options that are not consistent with more recent versions of the tasks. Changing those defaults would break existing Ant scripts.
When expanding properties in a string or text element, undefined properties are not raised as an error, but left as an unexpanded reference (e.g. ${unassigned.property}).
Ant has limited fault handling rules.
Lazy property evaluation is not supported. For instance, when working within an Antcontrib loop, a property cannot be re-evaluated for a sub-value which may be part of the iteration. (Some third-party extensions facilitate a workaround; AntXtras flow-control tasksets do provide for cursor redefinition for loops.)
In makefiles, any rule to create one file type from another can be written inline within the makefile. For example, one may transform a document into some other format by using rules to execute another tool. Creating a similar task in Ant is more complex: a separate task must be written in Java and included with the Ant build file in order to handle the same type of functionality. However, this separation can enhance the readability of the Ant script by hiding some of the details of how a task is executed on different platforms.
There exist third-party Ant extensions (called antlibs) that provide much of the missing functionality. Also, the Eclipse integrated development environment (IDE) can build and execute Ant scripts, while the NetBeans IDE uses Ant for its internal build system. As both these IDEs are very popular development platforms, they can simplify Ant use significantly. (As a bonus, Ant scripts generated by NetBeans can be used outside that IDE as standalone scripts.)