I'm using the Spring framework and have imported java.security.MessageDigest. My goal here is to produce a checksum verification. I want to output the checksum value, but I instead get this error when connecting to the server:
From my console:
java.lang.NoSuchMethodException: java.security.MessageDigest.<init>()
at java.base/java.lang.Class.getConstructor0(Class.java:3784) ~[na:na]
at java.base/java.lang.Class.getDeclaredConstructor(Class.java:2955) ~[na:na]
at org.springframework.web.method.annotation.ModelAttributeMethodProcessor.createAttribute(ModelAttributeMethodProcessor.java:216) ~[spring-web-5.2.3.RELEASE.jar:5.2.3.RELEASE]
at org.springframework.web.servlet.mvc.method.annotation.ServletModelAttributeMethodProcessor.createAttribute(ServletModelAttributeMethodProcessor.java:85) ~[spring-webmvc-5.2.3.RELEASE.jar:5.2.3.RELEASE]
at org.springframework.web.method.annotation.ModelAttributeMethodProcessor.resolveArgument(ModelAttributeMethodProcessor.java:139) ~[spring-web-5.2.3.RELEASE.jar:5.2.3.RELEASE]
at org.springframework.web.method.support.HandlerMethodArgumentResolverComposite.resolveArgument(HandlerMethodArgumentResolverComposite.java:121) ~[spring-web-5.2.3.RELEASE.jar:5.2.3.RELEASE]
at org.springframework.web.method.support.InvocableHandlerMethod.getMethodArgumentValues(InvocableHandlerMethod.java:167) ~[spring-web-5.2.3.RELEASE.jar:5.2.3.RELEASE]
at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:134) ~[spring-web-5.2.3.RELEASE.jar:5.2.3.RELEASE]
at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:106) ~[spring-webmvc-5.2.3.RELEASE.jar:5.2.3.RELEASE]
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:888) ~[spring-webmvc-5.2.3.RELEASE.jar:5.2.3.RELEASE]
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:793) ~[spring-webmvc-5.2.3.RELEASE.jar:5.2.3.RELEASE]
at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87) ~[spring-webmvc-5.2.3.RELEASE.jar:5.2.3.RELEASE]
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1040) ~[spring-webmvc-5.2.3.RELEASE.jar:5.2.3.RELEASE]
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:943) ~[spring-webmvc-5.2.3.RELEASE.jar:5.2.3.RELEASE]
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1006) ~[spring-webmvc-5.2.3.RELEASE.jar:5.2.3.RELEASE]
at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:898) ~[spring-webmvc-5.2.3.RELEASE.jar:5.2.3.RELEASE]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:634) ~[tomcat-embed-core-9.0.30.jar:9.0.30]
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:883) ~[spring-webmvc-5.2.3.RELEASE.jar:5.2.3.RELEASE]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:741) ~[tomcat-embed-core-9.0.30.jar:9.0.30]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231) ~[tomcat-embed-core-9.0.30.jar:9.0.30]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.30.jar:9.0.30]
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53) ~[tomcat-embed-websocket-9.0.30.jar:9.0.30]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.30.jar:9.0.30]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.30.jar:9.0.30]
at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100) ~[spring-web-5.2.3.RELEASE.jar:5.2.3.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.2.3.RELEASE.jar:5.2.3.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.30.jar:9.0.30]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.30.jar:9.0.30]
at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:93) ~[spring-web-5.2.3.RELEASE.jar:5.2.3.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.2.3.RELEASE.jar:5.2.3.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.30.jar:9.0.30]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.30.jar:9.0.30]
at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201) ~[spring-web-5.2.3.RELEASE.jar:5.2.3.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.2.3.RELEASE.jar:5.2.3.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.30.jar:9.0.30]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.30.jar:9.0.30]
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:202) ~[tomcat-embed-core-9.0.30.jar:9.0.30]
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96) ~[tomcat-embed-core-9.0.30.jar:9.0.30]
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:541) ~[tomcat-embed-core-9.0.30.jar:9.0.30]
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:139) ~[tomcat-embed-core-9.0.30.jar:9.0.30]
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92) ~[tomcat-embed-core-9.0.30.jar:9.0.30]
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:74) ~[tomcat-embed-core-9.0.30.jar:9.0.30]
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343) ~[tomcat-embed-core-9.0.30.jar:9.0.30]
at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:367) ~[tomcat-embed-core-9.0.30.jar:9.0.30]
at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65) ~[tomcat-embed-core-9.0.30.jar:9.0.30]
at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:860) ~[tomcat-embed-core-9.0.30.jar:9.0.30]
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1598) ~[tomcat-embed-core-9.0.30.jar:9.0.30]
at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) ~[tomcat-embed-core-9.0.30.jar:9.0.30]
at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1144) ~[na:na]
at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:642) ~[na:na]
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) ~[tomcat-embed-core-9.0.30.jar:9.0.30]
at java.base/java.lang.Thread.run(Thread.java:1570) ~[na:na]
To my understanding, this means the code is trying to call a default constructor that does not exist. I don't attempt this in my code. I instantiate the MessageDigest with SHA-256 as done in its documentation. Here's what I've written:
@SpringBootApplication
public class SslServerApplication {
public static void main(String[] args) throws NoSuchAlgorithmException {
SpringApplication.run(SslServerApplication.class, args);
ServerController controller = new ServerController();
// ServerController instance to run myHash
MessageDigest object = MessageDigest.getInstance("SHA-256");
// create MessageDigest object and initialize with cipher
controller.myHash(object);
}
}
@RestController
class ServerController{
// hash function to return the checksum value for the data string
@RequestMapping("/hash")
public String myHash(MessageDigest object) throws NoSuchAlgorithmException {
String data = "myName";
// data to be hashed
byte[] toArray = data.getBytes();
// byte array of data
byte[] digested = object.digest(toArray);
// generate byte hash of array using digest()
String hexdata = bytesToHex(digested);
// convert hash to hex
return "<p>data: myName, SHA-256" + hexdata;
// return the hex
}
// convert bytes to hex
// open source code from java2s.com
private String bytesToHex(byte[] digested) {
StringBuilder sb = new StringBuilder();
for (byte hashByte : digested) {
int intVal = 0xff & hashByte;
if (intVal < 0x10) {
sb.append('0');
}
sb.append(Integer.toHexString(intVal));
}
return sb.toString();
}
}
I have cleaned the project and installed updates found by my IDE (Eclipse) with no changes to the output. I'm not sure what else to try.
This error occurs because you specified MessageDigest as a parameter to the ServerController.myHash() method. So when you send a request to your application, Spring tries to create an instance of MessageDigest, but it can't do so because MessageDigest doesn't have an accessible constructor. You should remove MessageDigest from the parameters and move the MessageDigest creation code from the SslServerApplication.main() method to ServerController.myHash().