PostgreSQL - Fallo recibir query

Hola.
Necesito ayuda, estoy desesperado a intentar ejecutar dos sentencias con postgres.
En el pgAdmin me funcionan perfectamente pero al intentar enviar al query desde netbeans siempre me falla.
Tengo otras sentencias y funcionan a la perfección, debe ser fallo de código sql.
Netbeans me devuelve estos errores:
at org.postgresql.core.v3.QueryExecutorImpl.receiveErrorResponse(QueryExecutorImpl.java:2062)
at org.postgresql.core.v3.QueryExecutorImpl.processResults(QueryExecutorImpl.java:1795)
at org.postgresql.core.v3.QueryExecutorImpl.execute(QueryExecutorImpl.java:257)
at org.postgresql.jdbc2.AbstractJdbc2Statement.execute(AbstractJdbc2Statement.java:479)
at org.postgresql.jdbc2.AbstractJdbc2Statement.executeWithFlags(AbstractJdbc2Statement.java:353)
at org.postgresql.jdbc2.AbstractJdbc2Statement.executeQuery(AbstractJdbc2Statement.java:252)

// Tablas
CREATE TABLE "order"
(
id_user character varying(20) NOT NULL,
id_order integer NOT NULL,
ship character varying(25) NOT NULL,
payment character varying(25) NOT NULL,
payment_details character varying(35) NOT NULL,
commentary character varying(255),
total_price real NOT NULL,
CONSTRAINT order_pkey PRIMARY KEY (id_order)
)

CREATE TABLE product
(
id_product integer NOT NULL,
"name" character varying(20) NOT NULL,
description character varying(255) NOT NULL,
price real NOT NULL,
picture character varying(255) NOT NULL,
discount character varying(10) NOT NULL,
stock integer NOT NULL,
department character varying(30) NOT NULL,
CONSTRAINT product_pkey PRIMARY KEY (id_product)
)

CREATE TABLE trolley
(
id_product integer NOT NULL,
id_trolley integer NOT NULL,
id_user character varying(20) NOT NULL,
quantity integer DEFAULT 1,
CONSTRAINT trolley_pkey PRIMARY KEY (id_trolley)
)

// Sentencias
1) sentencia enviada desde netbeans:
stmt.executeUpdate("INSERT INTO order ('"+us+"',nextval('sec_order'), '"+shipping+"', '"+payment+"', '"+payment_details+"', '"+commentary+"', '"+total_price+"'");

2) sentencia enviada desde netbeans:
stmt.executeQuery("select order.id_order, trolley.id_product, product.name, trolley.quantity from order inner join trolley on order.id_user=trolley.id_user inner join product on trolley.id_product=product.id_product where trolley.id_user='"+us+"'");