How do I install JDK 1.6 in Mavericks?
You can download Java SE 6 for OS X from here: http://support.apple.com/kb/DL1572

For Maven support you can use brew (as stated above) or, if you don't want to install brew just for Maven support, you can download it directly from maven.apache.org. Here's the steps I took to get Maven setup on a fresh install of Mavericks:

curl -O http://apache.tradebit.com/pub/maven/maven-3/3.1.1/binaries/apache-maven-3.1.1-bin.tar.gz
sudo mkdir /usr/local
cd /usr/local
sudo tar -xf ~/apache-maven-3.1.1-bin.tar.gz
echo "export PATH=$PATH:/usr/local/apache-maven-3.1.1/bin" &gt;&gt; .profile
echo "export JAVA_HOME=/Library/Java/Home" &gt;&gt; .profile