in aws-serverless-java-container-core/src/main/java/com/amazonaws/serverless/proxy/internal/servlet/AwsCookieProcessor.java [39:46]
static BitSet createTokenValidSet() {
BitSet tokenSet = new BitSet(128);
for (char c = '0'; c <= '9'; c++) tokenSet.set(c);
for (char c = 'a'; c <= 'z'; c++) tokenSet.set(c);
for (char c = 'A'; c <= 'Z'; c++) tokenSet.set(c);
for (char c : "!#$%&'*+-.^_`|~".toCharArray()) tokenSet.set(c);
return tokenSet;
}