The following steps will help you to install java in ubuntu / debian  manually

Download the jdk 7 tar  file  http://www.oracle.com/technetwork/java/javase/downloads/index.html

mkdir -pv /usr/lib/jvm
cd /usr/lib/jvm
wget -c http://downloads-url-of-jdk/java/jdk-7u10-linux-x64.tar.gz
tar -xzf jdk-7u10-linux-x64.tar.gz
cd /usr/lib/jvm/jdk1.7.0_10

Now set the alternatives path

update-alternatives –install “/usr/bin/java” “java” “/usr/lib/jvm/jdk1.7.0_10/bin/java” 1
update-alternatives –install “/usr/bin/javac” “javac” “/usr/lib/jvm/jdk1.7.0_10/bin/javac” 1
update-alternatives –install “/usr/bin/javaws” “javaws” “/usr/lib/jvm/jdk1.7.0_10/bin/javaws” 1

Now edit the bashrc file and set teh following environment variables

export JAVA_HOME=/usr/lib/jvm/jdk1.7.0_10
export CLASSPATH=.:$JAVA_HOME/lib/
export PATH=$JAVA_HOME/bin:$PATH

Now you can test the java version using the following command,

# javac -version

PS: If you have multiple alternative , please configure it using   update-alternatives –config java