Getting a NullPointer instead of creating a token - spring-boot

Question

I'm currently writing a Spring Boot application using JWT. Testing the functionality responsible for creating a token using different dates I encountered a problem. Well, instead of a token I get NullPointer. That's how I test it:
#Test
public void testGenerateTokenFromDifferentDates() {
when(clockMock.now())
.thenReturn(DateUtil.yesterday())
.thenReturn(DateUtil.now());
String token = createToken();
String tokenLater = createToken();
assertThat(token).isNotEqualTo(tokenLater);
}
private String createToken() {
String token = tokenUtil.generateToken(new TestUser(USERNAME));
return token;
}
And this is the class responsible for creating the token:
#Component
public class TokenUtil implements Serializable {
private static final long serialVersionUID = -3301605591108950415L;
#Value("${jwt.secret}")
private String secret;
private Clock clock = DefaultClock.INSTANCE;
#Value("${jwt.expires.days}")
private Long expiration;
public String getUsernameFromToken(String token) {
return getClaimsFromToken(token, Claims::getSubject);
}
public <T> T getClaimsFromToken(String token, Function<Claims, T> resolverClaims) {
final Claims claims = getAllClaimsFromToken(token);
return resolverClaims.apply(claims);
}
public String generateToken(UserDetails userDetails) {
Map<String, Object> claims = new HashMap<>();
return doGenerateToken(claims, userDetails.getUsername());
}
private Claims getAllClaimsFromToken(String token) {
return Jwts.parser().setSigningKey(secret).parseClaimsJwt(token).getBody();
}
private String doGenerateToken(Map<String, Object> claims, String subject) {
final Date createdDate = clock.now();
final Date expirationDate = calculateExpirationDate(createdDate);
return Jwts.builder()
.setClaims(claims)
.setSubject(subject)
.setIssuedAt(createdDate)
.setExpiration(expirationDate)
.signWith(SignatureAlgorithm.HS512, this.secret)
.compact();
}
private Date calculateExpirationDate(Date createdDate) {
return new Date(createdDate.getTime() + expiration * 1000);
}
}
I can't think what the reason may be. Debugger also doesn't help me because it doesn't come to this moment. Here is the repository.
As #theonlyrao suggested here is the stack trace:
java.lang.NullPointerException
at com.github.springjwt.security.jwt.TokenUtil.calculateExpirationDate(TokenUtil.java:59)
at com.github.springjwt.security.jwt.TokenUtil.doGenerateToken(TokenUtil.java:47)
at com.github.springjwt.security.jwt.TokenUtil.generateToken(TokenUtil.java:38)
at com.github.springjwt.security.jwt.TokenUtilTest.createToken(TokenUtilTest.java:42)
at com.github.springjwt.security.jwt.TokenUtilTest.testGenerateTokenFromDifferentDates(TokenUtilTest.java:35)

Answer 1

It seems like either createdDate or expiration are null.
I'm not sure how createdDate get instantiated because I've not used that DefaultClock library.
I think the issue with expiration is that you haven't told Spring where to look for the the application properties in your test. Unless that happening elsewhere in code, you need to specific the path to the resource as described in https://www.baeldung.com/spring-classpath-file-access.