JAVA UTF-8 encoding

Many times developers are stuck with issues where arabic / hebrew / chinese characters in their application either look as junk characters or ???????? in their Backend Java based applications. 

 Why Does this happen. 

 1) Application Encoding Settings. Make sure your application is set to use the right encoding mechanism. the most important. (UTF-8) For example :- setting default in encoding in Apache Velocity

 2) Validating JVM Encoding Sometimes servers like tomcat , jboss etc might need to be started with an additional parameter for encoding For Eg.

3) Making Sure your IDE has the right encoding settings.

JAVA RSA 256 Private Key JWT Creation - OpenSSL Key Pair

Steps to create RSA256 Keypair using OpenSSL

You need to convert your private key to PKCS8 format using following command: This will ensure your code to read the PEM openssl pkcs8 -topk8 -inform PEM -outform DER -in C:\certs\2021.key -nocrypt > pkcs8_key.key

Please note that the rsa key you have need to be converted to der format online 

can be done using below link

https://decoder.link/rsa_converter
 

       
       
import java.io.UnsupportedEncodingException;
import java.security.Key;
import java.security.KeyFactory;
import java.security.NoSuchAlgorithmException;
import java.security.PrivateKey;
import java.security.spec.InvalidKeySpecException;
import java.security.spec.PKCS8EncodedKeySpec;
import java.time.LocalDateTime;
import java.time.ZoneId;
import java.util.Base64;
import java.util.Date;

import io.jsonwebtoken.Claims;
import io.jsonwebtoken.Jws;
import io.jsonwebtoken.Jwts;
import io.jsonwebtoken.SignatureAlgorithm;
import io.jsonwebtoken.impl.TextCodec;

public class JwtTokenUtilRSA {

	public static void main(String[] args) throws Exception {

		System.out.println(createAccessJwtToken());

	}

	public static String createAccessJwtToken() throws Exception {

		SignatureAlgorithm signatureAlgorithm = SignatureAlgorithm.RS256;
		Claims claims = Jwts.claims().setSubject("EXXXXXXXXciOSbWCwG");
		claims.put("aud", "XYZ.com");

		LocalDateTime currentTime = LocalDateTime.now();

		Key signingKey = getPrivateKey2();

		String token = Jwts.builder().setClaims(claims).setIssuer("issuer")
				.setIssuedAt(Date.from(currentTime.atZone(ZoneId.systemDefault()).toInstant()))
				.signWith(SignatureAlgorithm.RS256, signingKey).compact();

		return token;
	}
    
    	private static PrivateKey getPrivateKey2() throws NoSuchAlgorithmException, InvalidKeySpecException {
	    String rsaPrivateKey = "-----BEGIN PRIVATE KEY-----" +
	            "MIIEvgIBADANBgkqhkiG9w0BAQEFAASCBKgwggSkAgEAAoIBAQDJPwCTr8LDSi/7" +
	            "f0PXtiGZHcT/7B2AAIlATC178lp1mI42Exmw2X/yOiNU6mkiYQxxkv1vr8blViga" +
	            "mfhwCjahzI9ix0PzyEjVxfFWYlnfoorNGOwWgAqD3kzgnnUVPQXFmYRjtVD43sM4" +
	            "54h9Q1nFfPnVe9vgyckKI/p2nVUyZZlMo36/PRZdAV15vVvuvBJLW3gW3Xb2OuLy" +
	            "sF7/NEQe2zi5A87j4pbeRpBmGWzmloF3dNjwtCZAiSmX01nLe0bZYJIHgDgmPDKt" +
	            "qond8Pe1+zEDDf6fyq9mfT/naSOL1mQbLK2VQdGUGWmNgIpTgPEpolv3AdwbOtMx" +
	            "47GiOBPdAgMBAAECggEAeimjiQNNoEzdmbakkUJ/XLpEhvJm6ffpWT2k8rOok/Aa" +
	            "i9rGYqN1Vq5SGk79qR/udNc8v1qdy0Okrpk+xYx9o3RQqi66Ijc3d4VkPgMP+YBq" +
	            "75usXPA28du1ITkva8gSQ+QwCHLdh2V6boWmRhvnV8nIwv4f+HGld2FlvjE9sYwF" +
	            "Zwuo51G5TBkMnLaklHzMB18sTrcC4EmFvFfEsH6lzY3XaZXbMiwV802VbTasiXGi" +
	            "+HDMfUrxza1AVUz4zqlZhWvJL2c9RinLnSsS1eZ/FGbRrjZbfyE/IMFiMapP9LGi" +
	            "Cw1Gdt9NAwWtx78lgOrrW1+YYLVJEUlXZmPcPBkCZQKBgQDrP9tl10I8wlp6XyRY" +
	            "1Ge2xqAaSuHSwIMdSw9eRyO9K/CCV7hmzNOUvVe7U3Q5knxD5aoIul2Behn6BzDA" +
	            "hovtQALmFn0lmwsb7IKa/zM1o3BM5qrSwCTXSiBfKyi207jCK35wJPAJeemCl1JQ" +
	            "NY0Fug31/+SPLcGyO0HIcxaZrwKBgQDa/1HEHQ6yn2Eb3H/KtNrh5CQYu004LBaz" +
	            "ISsR7JwfyHscrE34Fx1eyEuJDVehGC30U61zh5h/dibr9M4wJqUTvJuhJh3X/w7r" +
	            "w1vWSE9rOJsOFenjWVv+2VO6TkaayWPDC79mCR/UBIXULOdMwi6NhDd8eqVraZzg" +
	            "b5TTHntqMwKBgB6KP7VM6LBymsRgLZvKl1xHFOnU5tQxYdQftnMK0Tzxw1tof+v4" +
	            "k08v9X/AKcp/ldpKqnRPnWv9qfmnjVCxJuE5+iZcrQqAwkRxw9LTZpaEDUQufea2" +
	            "QxIf8WvpcnOpsMakVtnAMdlJFmN5uZnoGdKwgLd67PUZf5ff0X5wUnLJAoGBAM60" +
	            "Itc6nf7XFG+ZxjzsS5TfI3r8fzw/0QUuj1qRvCL7tcgwkj9SgfROlY08vLNfATEW" +
	            "MidTmwrj2ITqQhuMvk9MvJB0S8LuCYValbpB8kQ/34qCAIsIcx6uvqqg6196KuGU" +
	            "mwmSHyqdQjwsTf1TY2FLpJunn68stlfYud4zbUWlAoGBAMCxCk2QabirfKSpKeXY" +
	            "On52j23o/8g2OfDPtd1cS30mTtDUStv3Sqr5Tegz+/7IwugORQujae4b20qgBSds" +
	            "NP9gb8RGmxLryZsEfwV1qppx0d1gEcyYcySYBhz+9qKyByeD8lotbZ0WGMu/UAg/" +
	            "ftaiqVv/CKA/h256T/5uThS3" +
	            "-----END PRIVATE KEY-----";

	    rsaPrivateKey = rsaPrivateKey.replace("-----BEGIN PRIVATE KEY-----", "");
	    rsaPrivateKey = rsaPrivateKey.replace("-----END PRIVATE KEY-----", "");

	    PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(Base64.getDecoder().decode(rsaPrivateKey));
	    KeyFactory kf = KeyFactory.getInstance("RSA");
	    PrivateKey privKey = kf.generatePrivate(keySpec);
	    return privKey;
	
	}

}