amazon ec2 tomcat java.security.InvalidAlgorithmParameterException: the trustAnchors parameter must be non-empty in Catalina Amazon EC2 AMI log when trying to access S3

Hard to figure out what was going on. Internet searches give wrong answer.

set JRE_HOME=/usr/local/jdk1.6_23 in catalina.sh in tomcat/bin

The Amazon EC2 Image uses openJDK and sets JRE_HOME to be in /usr. You have to use the Sun JRE to get around this error.