Explanation/Reference:
In online database mode, Oracle Loader for Hadoop can connect to the target database using the credentials provided in the job configuration file or in an Oracle wallet.
Oracle Wallet Manager is an application that wallet owners use to manage and edit the security credentials in their Oracle wallets. A wallet is a password-protected container used to store authentication and signing credentials, including private keys, certificates, and trusted certificates needed by SSL.
Note: Oracle Wallet Manager provides the following features:
Wallet Password Management

Strong Wallet Encryption

Microsoft Windows Registry Wallet Storage

Backward Compatibility

Public-Key Cryptography Standards (PKCS) Support

Multiple Certificate Support

LDAP Directory Support

References: https://docs.oracle.com/cd/B28359_01/network.111/b28530/asowalet.htm#BABHEDIE