Your java application unable to send the email after deploy in tomcat9 webserver

 

Issue
	===========
	Title - server is not sending the email through your appliation
	Descrp - sometimes the tomcat server installed in linux system is not able to send the email throgh your deployed webapplication
	even if you tested in local windows machine
	Solution
	===========
	soource - https://serverfault.com/questions/1062435/cannot-send-emails-from-tomcat-application
	The problem was with the last versions of Java.
	I had installed openjdk 1.8.0_292, since _291, doesn't allow TLS 1.0 and 1.1, protocol that Gmail has by default until today.
	So, to be able to solve my problem without install another versions of java, I had edited the file /usr/lib/jvm/java-8-openjdk-amd64/jre/lib/security/java.security
	And commented that part:
	#jdk.tls.disabledAlgorithms=SSLv3, TLSv1, TLSv1.1, RC4, DES, MD5withRSA, \
	#DH keySize < 1024, EC keySize < 224, 3DES_EDE_CBC, anon, NULL, \
	#include jdk.disabled.namedCurves
	And add this part right after:
	jdk.tls.disabledAlgorithms=SSLv3, RC4, DES, MD5withRSA, \
	DH keySize < 1024, EC keySize < 224, 3DES_EDE_CBC, anon, NULL, \
	include jdk.disabled.namedCurves1
	As you can see, the java had explicity disabled some protocols, returning the COULD NOT CONVERT SOCKET TO TLS error.
	Hope this help others who may find that problem.