3.-Hello-World-in-Java-using-Bazel.md

+## Installing Bazel
+
+This page describes the various platforms supported by Bazel and links
+to the packages for more details.
+
+The Bazel team officially supports Bazel on these platforms:
+
+*   [Ubuntu Linux](install-ubuntu.md)
+*   [macOS](install-os-x.md)
+*   [Windows](install-windows.md)
+
+## Install the JDK
+
+1.  Install Java JDK (preferred version is 11, however versions between 8 and 15 are supported).
+
+2.  Set the JAVA\_HOME environment variable to point to the JDK.
+    *   On Linux/macOS:
+
+            export JAVA_HOME="$(dirname $(dirname $(realpath $(which javac))))"
+    *   On Windows:
+        1.  Open Control Panel.
+        2.  Go to "System and Security" > "System" > "Advanced System Settings" > "Advanced" tab > "Environment Variables..." .
+        3.  Under the "User variables" list (the one on the top), click "New...".
+        4.  In the "Variable name" field, enter `JAVA_HOME`.
+        5.  Click "Browse Directory...".
+        6.  Navigate to the JDK directory (for example `C:\Program Files\Java\jdk1.8.0_152`).
+        7.  Click "OK" on all dialog windows.
+
+## Get the sample project
+
+Retrieve the sample project from Bazel's GitHub repository:
+
+```sh
+git clone https://github.com/evydtech/bazel-java.git
+```
+
+The sample project for this tutorial is in the `examples/java-tutorial`
+directory and is structured as follows:
+
+```
+java-tutorial
+├── BUILD
+├── src
+│   └── main
+│       └── java
+│           └── com
+│               └── example
+│                   ├── cmdline
+│                   │   ├── BUILD
+│                   │   └── Runner.java
+│                   ├── Greeting.java
+│                   └── ProjectRunner.java
+└── WORKSPACE
+```
+
+## Build with Bazel
+
+### Set up the workspace
+
+Before you can build a project, you need to set up its workspace. A workspace is
+a directory that holds your project's source files and Bazel's build outputs. It
+also contains files that Bazel recognizes as special:
+
+*  The `WORKSPACE` file, which identifies the directory and its contents as a
+   Bazel workspace and lives at the root of the project's directory structure,
+
+*  One or more `BUILD` files, which tell Bazel how to build different parts of
+   the project. (A directory within the workspace that contains a `BUILD` file
+   is a *package*. You will learn about packages later in this tutorial.)
+
+To designate a directory as a Bazel workspace, create an empty file named
+`WORKSPACE` in that directory.
+
+When Bazel builds the project, all inputs and dependencies must be in the same
+workspace. Files residing in different workspaces are independent of one
+another unless linked, which is beyond the scope of this tutorial.
+
+### Understand the BUILD file
+
+A `BUILD` file contains several different types of instructions for Bazel.
+The most important type is the *build rule*, which tells Bazel how to build the
+desired outputs, such as executable binaries or libraries. Each instance
+of a build rule in the `BUILD` file is called a *target* and points to a
+specific set of source files and dependencies. A target can also point to other
+targets.
+
+Take a look at the `java-tutorial/BUILD` file:
+
+```python
+java_binary(
+    name = "ProjectRunner",
+    srcs = glob(["src/main/java/com/example/*.java"]),
+)
+```
+
+In our example, the `ProjectRunner` target instantiates Bazel's built-in
+[`java_binary` rule](../be/java.html#java_binary). The rule tells Bazel to
+build a `.jar` file and a wrapper shell script (both named after the target).
+
+The attributes in the target explicitly state its dependencies and options.
+While the `name` attribute is mandatory, many are optional. For example, in the
+`ProjectRunner` rule target, `name` is the name of the target, `srcs` specifies
+the source files that Bazel uses to build the target, and `main_class` specifies
+the class that contains the main method. (You may have noticed that our example
+uses [glob](../be/functions.html#glob) to pass a set of source files to Bazel
+instead of listing them one by one.)
+
+### Build the project
+
+To build your sample project, navigate to the `java-tutorial` directory
+and run:
+
+```
+bazel build //:ProjectRunner
+```
+In the target label, the `//` part is the location of the `BUILD` file
+relative to the root of the workspace (in this case, the root itself),
+and `ProjectRunner` is the target name in the `BUILD` file. (You will
+learn about target labels in more detail at the end of this tutorial.)
+
+Bazel produces output similar to the following:
+
+```bash
+   INFO: Found 1 target...
+   Target //:ProjectRunner up-to-date:
+      bazel-bin/ProjectRunner.jar
+      bazel-bin/ProjectRunner
+   INFO: Elapsed time: 1.021s, Critical Path: 0.83s
+```
+
+Congratulations, you just built your first Bazel target! Bazel places build
+outputs in the `bazel-bin` directory at the root of the workspace. Browse
+through its contents to get an idea for Bazel's output structure.
+
+Now test your freshly built binary:
+
+```sh
+bazel-bin/ProjectRunner
+```
+
+Happy building!
\ No newline at end of file