JWT validation filter in Spring Boot - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to declare the filter class that extends the correct Spring Security filter.

Spring Boot

public class JwtValidationFilter extends [1] { }

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AHttpServlet

BOncePerRequestFilter

CFilterChain

DWebSecurityConfigurerAdapter

Attempts:

3 left

💡 Hint

Common Mistakes

Extending HttpServlet instead of OncePerRequestFilter

Using FilterChain as a class to extend

Extending WebSecurityConfigurerAdapter which is for configuration

The JwtValidationFilter should extend OncePerRequestFilter to ensure it runs once per request in Spring Security.

2fill in blank

medium

Complete the method signature to override the filter logic.

Spring Boot

@Override
protected void [1](HttpServletRequest request, HttpServletResponse response, FilterChain filterChain) throws ServletException, IOException { }

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AdoFilter

BprocessFilter

CfilterRequest

DdoFilterInternal

Attempts:

3 left

💡 Hint

Common Mistakes

Using doFilter instead of doFilterInternal

Using incorrect method names like filterRequest or processFilter

The method to override in OncePerRequestFilter is doFilterInternal.

3fill in blank

hard

Fix the error in extracting the JWT token from the Authorization header.

Spring Boot

String authHeader = request.getHeader("Authorization");
if (authHeader != null && authHeader.startsWith([1])) {
    String token = authHeader.substring(7);
}

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A"JWT "

B"Token "

C"Bearer "

D"Auth "

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'Token ' instead of 'Bearer '

Using 'JWT ' or 'Auth ' which are not standard prefixes

The standard prefix for JWT tokens in the Authorization header is "Bearer ".

4fill in blank

hard

Fill both blanks to validate the token and set authentication in the security context.

Spring Boot

if (jwtUtil.validateToken([1])) {
    UsernamePasswordAuthenticationToken authToken = new UsernamePasswordAuthenticationToken(
        userDetails, null, userDetails.[2]());
    SecurityContextHolder.getContext().setAuthentication(authToken);
}

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Atoken

BgetAuthorities

CgetCredentials

Duser

Attempts:

3 left

💡 Hint

Common Mistakes

Passing user instead of token to validateToken

Using getCredentials instead of getAuthorities

The token variable holds the JWT string to validate. The getAuthorities() method provides user roles for authentication.

5fill in blank

hard

Fill all three blanks to complete the filter chain call and handle exceptions properly.

Spring Boot

try {
    [1].doFilter([2], [3]);
} catch (JwtException e) {
    response.setStatus(HttpServletResponse.SC_UNAUTHORIZED);
}

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AfilterChain

Brequest

Cresponse

DauthToken

Attempts:

3 left

💡 Hint

Common Mistakes

Passing authToken instead of request or response

Calling doFilter on request or response instead of filterChain

The filter chain's doFilter method is called with the request and response objects to continue processing.