Perhaps you could have just read the documentation?
By default, the jarsigner command signs a JAR file using one of the following algorithms:
Digital Signature Algorithm (DSA) with the SHA1 digest algorithm
RSA algorithm with the SHA256 digest algorithm
Elliptic Curve (EC) cryptography algorithm with the SHA256 with Elliptic Curve Digital Signature Algorithm (ECDSA).
If the signer's public and private keys are DSA keys, then jarsigner signs the JAR file with the SHA1withDSA algorithm. If the signer's keys are RSA keys, then jarsigner attempts to sign the JAR file with the SHA256withRSA algorithm. If the signer's keys are EC keys, then jarsigner signs the JAR file with the SHA256withECDSA algorithm.
These default signature algorithms can be overridden using the -sigalg option