Short answer: it depends.
If you are completely restricted to Oracle javac and libraries, the answer is: no; for the following reasons.
Java bytecode contains a major version number. By default, a Java 8 compiler puts java8 into the data. Any older JVM simply refuses to run that code. It is possible though to tell a Java 8 compiler to create bytecode compatible to older JVMs. But: in order for the older JVM to execute such "special" class files, you need all its dependencies to be available!
And there it breaks: Lambdas make use of the invokedynamic bytecode instruction which doesn't exist in Java 6. And beyond that, the compiler makes use of a large number of Java library stuff when compiling lambdas - all of them added after java 6.
So even when you would manage to compile lambda using source code to Java 6 bytecode - that instruction isn't available,and you need to provide all those other classes, too.
But: as the other great answer explains, there are alternatives to javac which allow you to use lambdas on older JVMs.
But: be careful how to spend your energy. Java 6 is still dead for "server side java". So using these alternatives is OK for platforms like Android, but when you are still running an Oracle Java 6 JVM somewhere, you should rather spend your energy on upgrading that system to a current version of Java.
