Java code coverage tools are of two types: first, tools that add statements to the

Java Java (; id, Jawa, ; jv, ꦗꦮ; su, ) is one of the Greater Sunda Islands in Indonesia. It is bordered by the Indian Ocean to the south and the Java Sea to the north. With a population of 151.6 million people, Java is the world's List ...

source code In computing, source code, or simply code, is any collection of code, with or without comments, written using a human-readable programming language, usually as plain text. The source code of a program is specially designed to facilitate the wo ...

and require its recompilation. Second, tools that instrument the

bytecode Bytecode (also called portable code or p-code) is a form of instruction set designed for efficient execution by a software interpreter. Unlike human-readable source code, bytecodes are compact numeric codes, constants, and references (norma ...

, either before or during execution. The goal is to find out which parts of the code are tested by registering the lines of code executed when running a test.

JCov

JCov is the tool which has been developed and used with Sun JDK (and later Oracle JDK) from the very beginning of Java: from the version 1.1. JCov is capable of measuring and reporting

code coverage In computer science, test coverage is a percentage measure of the degree to which the source code of a program is executed when a particular test suite is run. A program with high test coverage has more of its source code executed during testing, ...

. JCov is distributed under the terms of the

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(version 2, with the Classpath Exception). JCov has become open-source as a part of OpenJDK code tools project in 2014.

Features

JCov is capable of reporting the following types of code coverage: * Block coverage * Line coverage * Branch coverage * Method coverage JCov implements two different ways to save the collected data: * Into a file on the filesystem * Onto a server