How to obtain RoleArn

[qq499212485]

How to obtain RoleArn？
I want to use STSToken to upload files, but need roleArn.
I try to invoke assumeRole was unsuccessful.

public Credentials assumeRole(String roleArn, String roleSessionName) {
		this.stsClient = StsClient.builder()
                .region("us_east_1")
                .credentialsProvider(credentialsProvider)
                .endpointOverride("192.168.1.240:9000")
                .build();
        try {
            AssumeRoleRequest roleRequest = AssumeRoleRequest.builder()
                .roleArn(roleArn)
                .roleSessionName(roleSessionName)
                .build();

            AssumeRoleResponse roleResponse = stsClient.assumeRole(roleRequest);
            Credentials myCreds = roleResponse.credentials();

            // Display the time when the temp creds expire.
            Instant exTime = myCreds.expiration();
            String tokenInfo = myCreds.sessionToken();

            // Convert the Instant to readable date.
            DateTimeFormatter formatter = DateTimeFormatter.ofLocalizedDateTime(FormatStyle.SHORT)
                .withLocale(Locale.US)
                .withZone(ZoneId.systemDefault());

            formatter.format(exTime);
            System.out.println("The token " + tokenInfo + "  expires on " + exTime);
            return myCreds;
        } catch (StsException e) {
            log.error("assumeGivenRole", e);
            return null;
        }
	}

software.amazon.awssdk.services.sts.model.StsException: (Service: Sts, Status Code: 400, Request ID: null) (SDK Attempt Count: 1)
at software.amazon.awssdk.services.sts.model.StsException$BuilderImpl.build(StsException.java:113)
at software.amazon.awssdk.services.sts.model.StsException$BuilderImpl.build(StsException.java:61)

I couldn't find a way to generate roleArn in the console.
Creating using iamClient was also unsuccessful.

[qq499212485]

I have successfully called the AssumRole interface, but the regular key created in the console cannot be called, resulting in a 400 error message. The key used to build Docker can be successfully called.
You don't need a real roleArn, just fill it in freely.
It should be necessary to set policy permissions.