In JSF based applications we would have see this exceptions "HTTP Status 500 - The absolute uri: http://java.sun.com/jsp/jstl/core cannot be resolved in either web.xml or the jar files deployed with this application". Main cause of this issue is required dependencies are missing in the deployment

org.apache.jasper.JasperException: The absolute uri: http://java.sun.com/jsp/jstl/core cannot be resolved in either web.xml or the jar files deployed with this application org.apache.jasper.compiler.DefaultErrorHandler.jspError(DefaultErrorHandler.java:56) org.apache.jasper.compiler.ErrorDispatcher.dispatch(ErrorDispatcher.java:278) org.apache.jasper.compiler.ErrorDispatcher.jspError(ErrorDispatcher.java:76) org.apache.jasper.compiler.TagLibraryInfoImpl.generateTldResourcePath(TagLibraryInfoImpl.java:242) org.apache.jasper.compiler.TagLibraryInfoImpl.(TagLibraryInfoImpl.java:124) org.apache.jasper.compiler.Parser.parseTaglibDirective(Parser.java:411) org.apache.jasper.compiler.Parser.parseDirective(Parser.java:469) org.apache.jasper.compiler.Parser.parseElements(Parser.java:1455) org.apache.jasper.compiler.Parser.parse(Parser.java:139) org.apache.jasper.compiler.ParserController.doParse(ParserController.java:227) org.apache.jasper.compiler.ParserController.parse(ParserController.java:100) org.apache.jasper.compiler.Compiler.generateJava(Compiler.java:199) org.apache.jasper.compiler.Compiler.compile(Compiler.java:356) org.apache.jasper.compiler.Compiler.compile(Compiler.java:336) org.apache.jasper.compiler.Compiler.compile(Compiler.java:323) org.apache.jasper.JspCompilationContext.compile(JspCompilationContext.java:564) org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:357) org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:403) org.apache.jasper.servlet.JspServlet.service(JspServlet.java:347) javax.servlet.http.HttpServlet.service(HttpServlet.java:725) 
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)

Solution:
Just to ensure below dependencies are added in your project