Merge pull request #7 from urielsalis/java-support

Add java support

compiled_starters/java/.gitattributes

@@ -0,0 +1 @@
+* text=auto

compiled_starters/java/.gitignore

@@ -0,0 +1,4 @@
+java_dns.jar
+target/*
+target/
+.idea/

compiled_starters/java/README.md

@@ -0,0 +1,37 @@
+![progress-banner](https://codecrafters.io/landing/images/default_progress_banners/dns-server.png)
+
+This is a starting point for Java solutions to the
+["Build Your Own DNS server" Challenge](https://app.codecrafters.io/courses/dns-server/overview).
+
+In this challenge, you'll build a DNS server that's capable of parsing and
+creating DNS packets, responding to DNS queries, handling various record types
+and doing recursive resolve. Along the way we'll learn about the DNS protocol,
+DNS packet format, root servers, authoritative servers, forwarding servers,
+various record types (A, AAAA, CNAME, etc) and more.
+
+**Note**: If you're viewing this repo on GitHub, head over to
+[codecrafters.io](https://codecrafters.io) to try the challenge.
+
+# Passing the first stage
+
+The entry point for your `your_server.sh` implementation is in
+`src/main/java/Main.java`. Study and uncomment the relevant code, and push your
+changes to pass the first stage:
+
+```sh
+git add .
+git commit -m "pass 1st stage" # any msg
+git push origin master
+```
+
+Time to move on to the next stage!
+
+# Stage 2 & beyond
+
+Note: This section is for stages 2 and beyond.
+
+1. Ensure you have `java (21)` installed locally
+1. Run `./your_server.sh` to run your program, which is implemented in
+   `src/main/java/Main.java`.
+1. Commit your changes and run `git push origin master` to submit your solution
+   to CodeCrafters. Test output will be streamed to your terminal.

compiled_starters/java/codecrafters.yml

@@ -0,0 +1,11 @@
+# Set this to true if you want debug logs.
+#
+# These can be VERY verbose, so we suggest turning them off
+# unless you really need them.
+debug: false
+
+# Use this to change the Java version used to run your code
+# on Codecrafters.
+#
+# Available versions: java-21
+language_pack: java-21

compiled_starters/java/pom.xml

@@ -0,0 +1,52 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+
+    <groupId>io.codecrafters</groupId>
+    <artifactId>build-your-own-dns</artifactId>
+    <version>1.0</version>
+
+    <properties>
+        <maven.compiler.source>21</maven.compiler.source>
+        <maven.compiler.target>21</maven.compiler.target>
+        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+        <java.version>21</java.version>
+    </properties>
+
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-assembly-plugin</artifactId>
+                <configuration>
+                    <finalName>java_dns</finalName> <!-- Please do not change this final artifact name-->
+                    <descriptorRefs>
+                        <descriptorRef>jar-with-dependencies</descriptorRef>
+                    </descriptorRefs>
+                    <appendAssemblyId>false</appendAssemblyId>
+                    <archive>
+                        <manifest>
+                            <addClasspath>true</addClasspath>
+                            <!-- This is the main class of your program which will be executed-->
+                            <mainClass>Main</mainClass>
+                        </manifest>
+                    </archive>
+                    <outputDirectory>${dir}</outputDirectory>
+                </configuration>
+
+                <executions>
+                    <execution>
+                        <id>make-assembly</id>
+                        <phase>package</phase>
+                        <goals>
+                            <goal>single</goal>
+                        </goals>
+                    </execution>
+                </executions>
+            </plugin>
+        </plugins>
+    </build>
+
+</project>

compiled_starters/java/src/main/java/Main.java

@@ -0,0 +1,27 @@
+import java.io.IOException;
+import java.net.DatagramPacket;
+import java.net.DatagramSocket;
+
+public class Main {
+  public static void main(String[] args){
+    // You can use print statements as follows for debugging, they'll be visible when running tests.
+    System.out.println("Logs from your program will appear here!");
+
+    // Uncomment this block to pass the first stage
+    //
+    // while(true) {
+    //   try(DatagramSocket serverSocket = new DatagramSocket(2053)) {
+    //     final byte[] buf = new byte[512];
+    //     final DatagramPacket packet = new DatagramPacket(buf, buf.length);
+    //     serverSocket.receive(packet);
+    //     System.out.println("Received data");
+    //
+    //     final byte[] bufResponse = new byte[512];
+    //     final DatagramPacket packetResponse = new DatagramPacket(bufResponse, bufResponse.length, packet.getSocketAddress());
+    //     serverSocket.send(packetResponse);
+    //   } catch (IOException e) {
+    //     System.out.println("IOException: " + e.getMessage());
+    //   }
+    // }
+  }
+}

compiled_starters/java/your_server.sh

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+#!/bin/sh
+#
+# DON'T EDIT THIS!
+#
+# CodeCrafters uses this file to test your code. Don't make any changes here!
+#
+# DON'T EDIT THIS!
+set -e
+mvn -B --quiet package -Ddir=/tmp/codecrafters-dns-target
+exec java -jar /tmp/codecrafters-dns-target/java_dns.jar "$@"

course-definition.yml

@@ -54,6 +54,8 @@ languages:
   - slug: "go"
   - slug: "python"
   - slug: "rust"
+  - slug: "java"
+    release_status: "beta"
 
 marketing:
   # Shown in the catalog.

dockerfiles/java-21.Dockerfile

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+FROM maven:3.9.5-eclipse-temurin-21-alpine
+
+COPY pom.xml /app/pom.xml
+
+WORKDIR /app
+
+# Download the dependencies
+RUN mvn -B package -Ddir=/tmp/codecrafters-dns-target
+
+# Cache Dependencies
+RUN mkdir -p /app-cached
+RUN mv /app/target /app-cached # Is this needed?
+
+# Pre-compile steps
+RUN echo "cd \${CODECRAFTERS_SUBMISSION_DIR} && mvn -B package -Ddir=/tmp/codecrafters-dns-target && sed -i 's/^\(mvn .*\)/#\1/' ./your_server.sh" > /codecrafters-precompile.sh
+RUN chmod +x /codecrafters-precompile.sh

solutions/java/01-init/code/.gitattributes

@@ -0,0 +1 @@
+* text=auto

solutions/java/01-init/code/.gitignore

@@ -0,0 +1,4 @@
+java_dns.jar
+target/*
+target/
+.idea/

solutions/java/01-init/code/README.md

@@ -0,0 +1,37 @@
+![progress-banner](https://codecrafters.io/landing/images/default_progress_banners/dns-server.png)
+
+This is a starting point for Java solutions to the
+["Build Your Own DNS server" Challenge](https://app.codecrafters.io/courses/dns-server/overview).
+
+In this challenge, you'll build a DNS server that's capable of parsing and
+creating DNS packets, responding to DNS queries, handling various record types
+and doing recursive resolve. Along the way we'll learn about the DNS protocol,
+DNS packet format, root servers, authoritative servers, forwarding servers,
+various record types (A, AAAA, CNAME, etc) and more.
+
+**Note**: If you're viewing this repo on GitHub, head over to
+[codecrafters.io](https://codecrafters.io) to try the challenge.
+
+# Passing the first stage
+
+The entry point for your `your_server.sh` implementation is in
+`src/main/java/Main.java`. Study and uncomment the relevant code, and push your
+changes to pass the first stage:
+
+```sh
+git add .
+git commit -m "pass 1st stage" # any msg
+git push origin master
+```
+
+Time to move on to the next stage!
+
+# Stage 2 & beyond
+
+Note: This section is for stages 2 and beyond.
+
+1. Ensure you have `java (21)` installed locally
+1. Run `./your_server.sh` to run your program, which is implemented in
+   `src/main/java/Main.java`.
+1. Commit your changes and run `git push origin master` to submit your solution
+   to CodeCrafters. Test output will be streamed to your terminal.

solutions/java/01-init/code/codecrafters.yml

@@ -0,0 +1,11 @@
+# Set this to true if you want debug logs.
+#
+# These can be VERY verbose, so we suggest turning them off
+# unless you really need them.
+debug: false
+
+# Use this to change the Java version used to run your code
+# on Codecrafters.
+#
+# Available versions: java-21
+language_pack: java-21

solutions/java/01-init/code/pom.xml

@@ -0,0 +1,52 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+
+    <groupId>io.codecrafters</groupId>
+    <artifactId>build-your-own-dns</artifactId>
+    <version>1.0</version>
+
+    <properties>
+        <maven.compiler.source>21</maven.compiler.source>
+        <maven.compiler.target>21</maven.compiler.target>
+        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+        <java.version>21</java.version>
+    </properties>
+
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-assembly-plugin</artifactId>
+                <configuration>
+                    <finalName>java_dns</finalName> <!-- Please do not change this final artifact name-->
+                    <descriptorRefs>
+                        <descriptorRef>jar-with-dependencies</descriptorRef>
+                    </descriptorRefs>
+                    <appendAssemblyId>false</appendAssemblyId>
+                    <archive>
+                        <manifest>
+                            <addClasspath>true</addClasspath>
+                            <!-- This is the main class of your program which will be executed-->
+                            <mainClass>Main</mainClass>
+                        </manifest>
+                    </archive>
+                    <outputDirectory>${dir}</outputDirectory>
+                </configuration>
+
+                <executions>
+                    <execution>
+                        <id>make-assembly</id>
+                        <phase>package</phase>
+                        <goals>
+                            <goal>single</goal>
+                        </goals>
+                    </execution>
+                </executions>
+            </plugin>
+        </plugins>
+    </build>
+
+</project>

solutions/java/01-init/code/src/main/java/Main.java

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+import java.io.IOException;
+import java.net.DatagramPacket;
+import java.net.DatagramSocket;
+
+public class Main {
+  public static void main(String[] args){
+    while(true) {
+      try(DatagramSocket serverSocket = new DatagramSocket(2053)) {
+        final byte[] buf = new byte[512];
+        final DatagramPacket packet = new DatagramPacket(buf, buf.length);
+        serverSocket.receive(packet);
+        System.out.println("Received data");
+
+        final byte[] bufResponse = new byte[512];
+        final DatagramPacket packetResponse = new DatagramPacket(bufResponse, bufResponse.length, packet.getSocketAddress());
+        serverSocket.send(packetResponse);
+      } catch (IOException e) {
+        System.out.println("IOException: " + e.getMessage());
+      }
+    }
+  }
+}

solutions/java/01-init/code/your_server.sh

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+#!/bin/sh
+#
+# DON'T EDIT THIS!
+#
+# CodeCrafters uses this file to test your code. Don't make any changes here!
+#
+# DON'T EDIT THIS!
+set -e
+mvn -B --quiet package -Ddir=/tmp/codecrafters-dns-target
+exec java -jar /tmp/codecrafters-dns-target/java_dns.jar "$@"

solutions/java/01-init/diff/src/main/java/Main.java.diff

@@ -0,0 +1,41 @@
+@@ -1,27 +1,22 @@
+ import java.io.IOException;
+ import java.net.DatagramPacket;
+ import java.net.DatagramSocket;
+
+ public class Main {
+   public static void main(String[] args){
+-    // You can use print statements as follows for debugging, they'll be visible when running tests.
+-    System.out.println("Logs from your program will appear here!");
++    while(true) {
++      try(DatagramSocket serverSocket = new DatagramSocket(2053)) {
++        final byte[] buf = new byte[512];
++        final DatagramPacket packet = new DatagramPacket(buf, buf.length);
++        serverSocket.receive(packet);
++        System.out.println("Received data");
+
+-    // Uncomment this block to pass the first stage
+-    //
+-    // while(true) {
+-    //   try(DatagramSocket serverSocket = new DatagramSocket(2053)) {
+-    //     final byte[] buf = new byte[512];
+-    //     final DatagramPacket packet = new DatagramPacket(buf, buf.length);
+-    //     serverSocket.receive(packet);
+-    //     System.out.println("Received data");
+-    //
+-    //     final byte[] bufResponse = new byte[512];
+-    //     final DatagramPacket packetResponse = new DatagramPacket(bufResponse, bufResponse.length, packet.getSocketAddress());
+-    //     serverSocket.send(packetResponse);
+-    //   } catch (IOException e) {
+-    //     System.out.println("IOException: " + e.getMessage());
+-    //   }
+-    // }
++        final byte[] bufResponse = new byte[512];
++        final DatagramPacket packetResponse = new DatagramPacket(bufResponse, bufResponse.length, packet.getSocketAddress());
++        serverSocket.send(packetResponse);
++      } catch (IOException e) {
++        System.out.println("IOException: " + e.getMessage());
++      }
++    }
+   }
+ }

solutions/java/01-init/explanation.md

@@ -0,0 +1,30 @@
+The entry point for your dns implementation is in `src/main/java/Main.java`.
+
+Study and uncomment the relevant code: 
+
+```java
+// Uncomment this block to pass the first stage
+
+while(true) {
+  try(DatagramSocket serverSocket = new DatagramSocket(2053)) {
+    final byte[] buf = new byte[512];
+    final DatagramPacket packet = new DatagramPacket(buf, buf.length);
+    serverSocket.receive(packet);
+    System.out.println("Received data");
+
+    final byte[] bufResponse = new byte[512];
+    final DatagramPacket packetResponse = new DatagramPacket(bufResponse, bufResponse.length, packet.getSocketAddress());
+    serverSocket.send(packetResponse);
+  } catch (IOException e) {
+    System.out.println("IOException: " + e.getMessage());
+  }
+}
+```
+
+Push your changes to pass the first stage:
+
+```
+git add .
+git commit -m "pass 1st stage" # any msg
+git push origin master
+```