编译android内核和文件系统，已经安装jdk，提示build/core/config.mk:268: *** Error: could not find jdk tools.jar

1：确保安装jdk，如果没有安装请移布：http://www.cnblogs.com/jiuyueguang/p/3156621.html

2：如果已经安装了jdk，还是提示此错误，

解决方法

请确保你的jdk在/usr/lib/jvm下

sudo update-alternatives --install /usr/bin/java java /usr/lib/jvm/jdk1.6.0_30/bin/java 300  
sudo update-alternatives --install /usr/bin/javac javac /usr/lib/jvm/jdk1.6.0_30/bin/javac 300  
sudo update-alternatives --install /usr/bin/javah javah /usr/lib/jvm/jdk1.6.0_30/bin/javah 300
sudo update-alternatives --install /usr/bin/jar jar /usr/lib/jvm/jdk1.6.0_30/bin/jar 300

3：重新编译内核